Page 6 – Sparky's Answers

2010 Toyota Tacoma IG1 2 Fuse Blows – Battery Goes Dead

This 2010 Toyota Tacoma came in with the complaint that the IG1 No2 fuse would blow sometimes. The IG1 NO2 fuse is located in the interior fuse box behind this panel.

After pulling the door open the whole unit can be lifted up and off of the hinge detents.

The interior fuse box legend with the location of the IG1 NO2 fuse being pointed to.

The actual 10 amp IG1 NO2 fuse in the interior fuse box.

I will admit that this is the first time that I have encountered this exact problem on this vehicle so I had a little bit of a learning curve as to what all is on this fuse circuit. Turns out that almost every system is affected when this fuse blows. According to the customer most of the warning lights on the dash would come including the ABS, Traction, Brake and SES lights. He also stated that the a/c and power windows would stop working. Eventually the battery would go dead while driving indicating that the alternator was not charging either. The owner stated that replacing the fuse would last several days to several weeks when the problem first started. It had gotten worse and the fuse would sometimes blow as soon as it was replaced and the key switched back on. As luck would have it it had not blown in several days before being brought to my shop. There was a code P0500 stored in history.

I looked through wiring diagrams and consulted several resources looking for a lead in what could be blowing this fuse and found that there are quite a few others in pursuit of the same answer. My first inclination was to the overhead compass above the rear view mirror since they have a history of not working and loose resistor floating around on the circuit board. The unit in this truck was working properly and light bumping with the heel of my hand made no difference.

I started my visual inspection under he hood and looked in all of the usual places around hot exhaust and sharp metal brackets but could not find anything.

I was inspecting the harness connector at the alternator when I spotted this. A wiring harness very close to a bolt head and bracket with a slight rust discoloration near it. You cannot really see it in the following picture …

…. so I went and looked through the inner fender opening to get a better look. See that tiny bit of powdery rust between the bolt head and the wiring harness. That was the evidence I was looking for.

After unplugging the green harness connector from the alternator I was able to move the harness away using a long screwdriver. Now a shiny spot was visible on the metal bracket.

Pulling the harness further away and looking at it from the topside showed heavy rub and rust marks on the harness tape.

I did not get any pictures because of the tight working area but I did use a test light and confirmed that there was power on the wires inside that rusted spot with the ignition on and a good IG1 NO2 fuse installed. I removed that fuse and the power went away proving that this was indeed a shorted wire on that fuse circuit.

I proceeded to remove the split loom and tape from that short section of wiring harness. After that I wiped the rust residue from the area and could see the damage on the light green wire. Enlarging the next image makes the damage easy to see.

The best way to repair this wire would be to remove the entire harness from this corner of the engine. Repair it and then re install it. A ton of work so I decided to go a different route. After removing the white internal terminal retainer I was able to release the internal terminal latch. This allowed the terminal and wire to be pulled free of the connector body. I then slid heat shrink tubing over the terminal and down the wire to the insulation damage. The internal wire was okay. Only one strand had been nicked. I reassembled it all including a new piece of split loom that would also cover the area better that the original had.

No to make sure this never happens again. Using a pair of slip joint pliers I was able to bend the edge of the steel bracket down and compress it onto the aluminium housing it was attached to. That by itself gave an extra 1/8″ to 3/16″ of room between the harness and the bracket.

Wanting to do a little better I split a piece of hose and placed it between the harness and the bracket.

I then squeezed in some sealant to act as a glue to hold the rubber wedge in place. The customer agreed to allowing the vehicle to mostly sit for a day to let it cure out.

As many of you already know my motto is to start inspecting/testing and stop guessing. This repair is a definite example of how to do that. As many inquiries as there are about this issue, I am sure this is not the only Toyota Tacoma that has this exact problem.

2004 Mazda Tribute Stalls in Drive-Code P0320 Stored

This 2004 Mazda Tribute came in with the complaint that engine stalls when the transmission is placed into drive. It also stalls when coming to a stop. It does not stall in reverse or neutral. Checking codes found a code P0320 stored for a crank sensor fault. As most of you should know a Mazda Tribute, Ford Escape and Mercury Mariner are all the same vehicle. So this problem and repair apply to all three over various years with the V6 engine.

Dropping a splash shield found that the crank sensor has already been replaced.

I did take the time to inspect the harness connector for loose terminal fit and any wiring problems in the general area. None were found.

I looked closely at the engine compartment harnesses while someone else shifted the transmission between reverse and drive and back again. I saw where the engine harness flexed substantially. It was between the top rear of the engine and where the PCM is mounted in the firewall, above the engine.

I had to remove the tape around the split loom so that I could open up the harness. After looking at a wiring diagram I knew that I would be looking for problems on either the black/pink wire @ terminal 21 or the gray/yellow wire @ terminal 22. When I pulled both wires out of the 104 pin PCM harness connector the problem was obvious. The bend in the black/pink wire indicated an internal break.

Pulling on the wire also showed that the wire was broken inside the insulation. The insulation would stretch and change color when pulled on.

A local salvage yard supplied a used 104 pin PCM harness so that I could splice in a replacement for the damaged wire. There are four locking tabs that have to be released in order to remove the black strain relief cover.

The red terminal positive assurance clip can be removed as shown below.

Using an angled pick the internal terminal retainer can be moved, so that the wire and terminal can be pulled out of the harness connector body.

The long edge of the pick has to be slid down the side of the terminal that is being removed. It will stop on the edge of the internal plastic retainer and the plastic retainer then has to be flexed away from the terminal. The wire and terminal needs to be gently pulled at the same time to keep the terminal unlocked from the housing.

The wire and terminal pull out of the connector body as shown below.

The terminal holes are numbered on the rear outer edges of the gray harness connector body.

The wire repaired and back in the harness. I replaced the wire with a longer piece of wire so that the splice joint would not be at the previous position of highest flexing. Had I not moved it away, it would have broken again in a short time. Note that the two wires are in what is referred to as a twisted pair and that I maintained the twist in the repair.

I also re wrapped the metal tape around the twisted pair.

I finished by reinstalling the split loom and wrapping it with electrical tape. Then I secured it all to the black strain relief cover on the PCM harness connector.

I strongly encouraged the owner to have the motor and transmission mounts replaced. They were worn and were the primary cause of the harness failure.

2004 Nissan Frontier-Gauges Inop-Code P0500

This 2004 Nissan Frontier came in with the complaint that the gauges had been working erratically for several months but not they have stopped working altogether. The customer had stated that the gauges and odometer would stop working and that he would tap on the dash and they would come back on. The also said that the truck would feel like it was pulling back when the gauges stopped and like it was surging forward when the came back on. There was also a code P0500 stored in the PCM. Looking at a wiring diagram showed that the Vehicle Speed Sensor (VSS) signal is sent to the instrument cluster and from there it is sent to the PCM. In 90% of cases the vehicle speed sensor would be the most likely cause of this problem but two things change that scenario. All of the gauges & the odometer stop working in unison and that for quite a while the owner was able to restore gauge function by tapping on the dash. This diagnosis is now trending towards a poor connection at the harness connectors or inside the instrument cluster. I know this repair will apply to several different years and models of Nissans, hopefully you will leave some of that information in the discussions area at the end of this article.

There are several things that have to be removed in order to check the Instrument Panel Cluster (IPC) starting with the steering column covers. There are several phillips headed screws that have to be removed from the underside of the steering column.

The two covers can then be separated.

Rocking the lower cover to the right or center of the vehicle will cause the ring around the key area to pop off easily.

Using the tilt handle on the left side of the column the steering column can be moved around to make the cover removal easier.

There are two phillips headed screws at either lower corner of the under dash knee bolster panel.

From there it just pulls towards the driver’s seat for removal. You can see a few of the spring tabs that secure it to the dash in the next image. The harness connectors will also need to be removed from the switches.

Now the IPC trim panel can be removed. It has the same kind of spring tabs holding it in place.

The turn signal indicator bulbs have to be removed from the panel. They just twist and pull out.

There are three phillips headed screws that hold the IPC to the dash carrier. On at the top center and two at either lower corner. Once they are removed the IPC can be pulled forward enough to work with disconnecting the harness connectors.

They both have locking tabs that have to be depressed before pulling the harnesses loose.

This securing cable tie also need to be pulled loose from the dash. A firm grip and a little wiggling is needed.

This mini harness needs to be disconnected at the edge of the IPC before disassembly of the actual cluster.

There are multiple tabs that have to be lifted as the rear cover is being lifted from the IPC.

Once the rear cover is removed look at the lower right side of the circuit board. There are three solder joints in a horizontal row. A close inspection found one clearly open solder joint and two others that were deteriorating.

The solder joint after they were resoldered. I know that you may not be able to see everything in these images that I could in person but the point is to show you where to look.

All back together and working.

Nearly 264,000 miles on this little truck.

This repair took listening to the customer, some testing, in depth understanding of how the systems work and careful inspection to complete.

2001 Dodge Dakota Hazard-Stop-Turn Signal Lights Not Working

This 2001 Dodge Dakota came in with the complaints that the turn signals, stoplights and hazards lights all quit working. This repair will generally apply to 2001, 2002, 2003 and 2004 Dakota and Durango vehicles. Testing begins with checking fuse 19 in the interior fuse box and fuse 1 in the power distribution center under the hood. Fuse 19 in the interior fuse box needs to be checked with the ignition on. Both fuses tested good and were properly powered.

The next step is to check the circuits at the combination flasher located under the driver’s side of the dash. The parking brake handle was missing on this Dakota so I can’t show how to disconnect it.

There are three screws along the lower edge of the knee bolster panel that need to be removed. In this case a T20 bit was needed.

With those screws removed the panel can be rocked and pulled towards the driver’s seat in order to disengage the spring clips.

In the following image i am grasping the combination flasher and the harness connector with bracket.

There is a locking tab that has to be released so that the assembly can be removed from the metal bracket.

It takes a little maneuvering to get the assembly positioned to where testing can begin.

The combination flasher will pull out of the harness connector/mounting base. Note that it has two sets of connectors that look like two relays sitting side by side.

The top of the combination flasher with the oem part number on it, 56049114AA.

Now for testing. With the ignition on there should be power on the small black wire as shown below.

There should be constant battery power on the larger black wire with a white stripe.

There should be power on the tan/white wire when the brake pedal is depressed.

Now testing switches gears a little. Since we had determined that there was battery power at all times at the black/white wire we are now going to use a jumper wire to connect the clamp of the test light to the circuit. Now that the clamp is connected to battery power we are ready to check the switched ground circuits.

Turning the hazard switch on while backprobing the pink wire turns the test light on proving that the hazard switch is good.

Turning the right turn signal on while backprobing the light blue/yellow wire proves that the right side of the turn signal switch is working properly.

The same test is done on the light blue/white wire while turning on the left turn signal.

Since all tests were positive the diagnosis is a faulty combination flasher assembly. A new combination flasher was installed and it resolved all three problems. As always remember to stop guessing and start testing.

2003 Ford F350 Radio & Power Windows Stop Working

This 2003 Ford F350 Super Duty Lariat Pickup came in with the complaint that the radio would turn off while driving down the road. At the same time the power windows and the dome light would no longer work. Sometimes hitting a bump in the road or tapping on the top of the dash would make the problem go away. The problem would sometimes only happen for a few minutes or it may last for days. Based on the customer’s explanation of the problem and statistical repair records I wanted to look at the accessory delay relay connections on the instrument cluster circuit board. The first step in getting to the IPC is to remove the radio. A special tool is required. If you work on Ford vehicles for living chances are that you already own a set of these. If not they can usually be found at most parts stored.

After inserting the “U” shaped tool into the holes in the radio you should notice that the angle in a little bit. By pushing out on the tool the retaining clips are released and the radio can be removed. If you do not mind the bulk and awkwardness of it the radio can be pulled out with the main dash trim panel in most cases.

The antenna cable on the right and one harness connector on the left have to be removed from the radio. Depending on options there may be more connectors attached to the radio.

The dash trim panel is held in place by spring style clips and …

…can be pulled away from the main dash carrier panel.

There is wiring that will need to be disconnected from the rear of the trim panel as it is removed. Headlight switch wiring is shown below. Other wiringcincludes the four wheel drive switch and power outlet.

The instrument cluster is held in place by four screws with 7 mm head. The shift indicator has to be removed from the underside of the cluster by gently squeezing in the latches on either side. The indicator will then slide down and out of the cluster. Use care as it is a delicate part. More so as it ages. There are several harness connectors attached to the rear of the instrument cluster.

Once the cluster is removed from the vehicle the white plastic cover on the rear of the cluster will need to be removed. Sorry no picture of actual removal but you can see it in the above picture and it is already removed in the picture below. The ribbon cable connector needs to be disconnected as shown in the next two images. Gently pry out on the securing latches…

…while pulling up on the ribbon cable harness connector.

The circuit board can now be lifted from the rear of the cluster assembly. It needs to be lifted smoothly and in large sections to avoid damaging the circuit board.

Here is the accessory delay relay.

Here are the faulty/cracked solder joints.

Close inspection did reveal that the solder joints were cracked/faulty and all eight solder joints related to the two relays were resoldered.

Although my motto is stop guessing and start testing this repair involved more inspecting than testing.

2009 Chevrolet Silverado Driver’s Side Air Stuck On Heat

This 2009 Chevrolet Silverado came in with the complaint that the a/c was blowing out hot air on the driver’s side of the dash.The vent temperature was 140°F and the outside air temperature was 97°F in August in sunny South Carolina. I told the customer that I would not be able to get to it until the next day. He said “Okay” and tossed me the keys. “I can’t drive it like that, call me when it is fixed”. The next morning I start of the diagnosis and found a code B0413 stored for a fault with the driver’s side temperature door actuator. No big surprise here. The replacement of the actuator is made easier than in past models with the redesign of the center console. Now there is a panel that will unclip and can be moved out of the way.

Having more room in this area makes removing the 3rd screw that holds the hush panel in place much easier. I used a 7 mm deep well socket on a 1/4″ ratchet with a flex head.

I have a couple of bushings that I keep together and slide up into the recessed hole for the screw. It makes placing the socket on the screw head much easier for both removal and re installation of the screw.

Replacing the actuator is pretty cut and dry. One harness connector with a thumb latch securing it to the actuator and two 5.5 mm headed screws attaching it to the HVAC case. I used a medium length 5.5 mm socket and the same 1/4″ drive flex head ratchet.

The old actuator. The replacement part can be found here.

I have been working with a new scan tool for me, the Autel MaxiSys Pro and it has one step in the recalibration procedure that I really like. After entering the HVAC system the “Special Function” button is available.

Within the “Special Function” section “Actuator Recalibration” is available. This is normal for most professional grade scan tools.

As one proceeds through the routine, instructions are given and command buttons made available.

Down to the actual “Calibration” button.

Here is where things are different compared to other scan tools I have used including the GM Tech 2 scan tool. There is an actual progression bar…

… to let you know that something is really going on and where in the procedure you are at. If you read one of the earlier screenshots it stated that the procedure could take up to 40 seconds which is standard for most post 2003 vehicles. During this time one hears the blower speed changing and the air flow directions moving about but always a little unsure of whether it is complete or not.

Now with this tool there is no more guessing or looking at a clock.

After following the last instructions to turn the ignition off and check for codes the system is clear of fault codes.

Looking at the data for the left temperature door you can see that the actual versus commanded counts are equal at 233 counts.

I know it may be a minor thing but having that extra feature sure is nice. Other things that I like about this scan tool are increased programming functions in both software programming and settings within user programmable modules. I was able to disable the Global Window setting on a 2005 Ford Mustang GT. On top of that the scan tool operates on a fast Android platform in a convenient wireless tablet platform. I look forward to seeing what else this scan tool will allow me to do in the future. A big thanks to Matt and the rest of the team at Advance Auto Parts for making this tool available and affordable to a small shop such as mine.

I look forward to being able to expand my testing abilities with this scan tool, the Autel MaxiSys Pro. After all my motto is to “stop guessing and start testing”.

Why Does Your Battery Go Dead?

“Why does my car or truck battery go dead?” is probably the most common question asked in the world of automotive electrical repair. The reasons can be broken down into four general causes.

The battery is faulty.
The charging system is not working properly.
There is a drain on the system.
Faulty cable connections

The very first bit of inspection and or testing should be to check the condition of the battery terminal connections. All other tests are irrelevant if the connections are poor. The following images are of clearly poor connections. The appearance does not have to be nearly as bad for the result to be the same.

Remember that each cable has at least two ends and sometimes the poor connection is not at the battery.

There can be some overlap in how the symptom presents itself so you should pay attention to the details. Investing in the proper tools to test with makes diagnosis quicker and more accurate.

There are some simple things that can be done to narrow the problem down though.

Does the battery go dead while the vehicle is being driven or while the vehicle is parked?

The battery going dead while driving scenario is generally associated with driving along and minding your own business when you start noticing things going on like: the battery light comes on, the headlights get dim, the radio cuts out, the turn signals stop flashing, multiple warning lights come on in the dash, the engine stalls and will not restart without a boost/jump start. These symptoms all leading up to the resulting dead battery indicate that there is something wrong with the charging system. The charging system fault could be caused by a faulty alternator or generator, a damaged or missing drive belt, faulty voltage regulator, cable connections, wiring problems, blown fuses and faulty control systems. Rarely a battery can have an internal short that the charging system cannot overcome. The battery will be every hot to the touch and there may be a lot of out gassing (rotten egg smell) present.

The battery going dead while sitting complaint is generally associated with no noticeable problem until you enter the vehicle and find that the battery is dead. The time frames involved in this scenario play an important role in diagnosing the problem.

If the battery is dead shortly after the engine is intentionally turned off it is highly likely that the battery is bad.
If the battery is dead 8 to 24 hours later, the battery is still the most likely cause but now there is a chance that there may be a significant drain on the system.
If the battery is dead in 24 hours to several days of the vehicle sitting the battery could still be faulty but the chances of a drain on the system being the problem go up dramatically.
Regardless of the time frame, if the engine starts immediately and crisply after a proper boost/jump start it increases the chances that the battery is bad.
If shortly after turning the engine off, the engine is slow to start and the starter sounds like it is dragging after being properly jump started the battery could still be faulty but the chances go up that it is a cable or starter issue and not a battery.
If there is a rapid clicking or chattering sound at the starter area when trying to start the engine there is a low voltage condition. Most of the time the problem will be poor cable connections or a faulty battery.

I will be building on this article overtime so expect changes or additions to the above content. If you want to add to the discussion please sign up for a basic membership to enable that function.

August 20,2016 update:

Okay, you go out to your car or truck to start it and you are now faced with what appears to be a dead battery. What do you do first? Unless you happen to have a voltmeter in your hand you should turn off all power consuming devices. Especially those that make noise. Then turn the ignition switch off. Now with your eyes and ears wide open and ready for observation turn the ignition on. Do not try to start the engine at this time. Do all of the dash warning lights come on like they normally do? Do you hear and type of clicking, ticking or chattering noises? Assuming all is normal, slowly turn the key to the crank position. What do you observe?

If you hear a rapid clicking or chattering sound as the key is held in the crank position and the dash warning lights dim significantly you have encountered a true low voltage condition. The potential low voltage condition can be further confirmed by turning on the headlights and observing their brightness through the key off-key on-crank procedure performed earlier. You may need assistance depending on the time of day and the ambient lighting. If the lights start off normal or dim and get dimmer as you try to start the engine you have low voltage. If they are normal/bright and only dim a very slight amount in the crank position you likely do not have a low voltage condition.
No discernible noise or one solid click and a slight dimming of the dash warning lights would point more to an internal problem in the starter and not a battery issue. Sometimes this problem can be further diagnosed and temporarily overcome by boosting the battery voltage with a battery charger or another vehicle that is running. If the starter is accessible it can be tapped on with a hammer or other heavy tool in the brush area to temporarily re seat the brushes that are worn out.

Now that you have determined that you have encountered a low voltage situation what do you do next? Again assuming that you do not have a voltmeter handy the next logical step would be to try and boost the battery voltage with a battery charger or another battery and jumper/booster cables. Before connecting anything to the battery take a second and feel the temperature of the battery terminals. Use a light touch as sometimes they can be very warm or even hot to the touch. If you encounter one or both that are warmer than the other or the surrounding materials you should stop and clean the battery terminals. Loose or corroded connections add resistance to a circuit. Combine resistance with a high current load (cranking the engine) and you create heat. Heat in any electrical circuit is an indicator of a problem with that circuit unless it is designed to create heat or regulate current.

2007 Chevrolet Monte Carlo SS Emissions 1 Fuse Blows

This 2007 Chevrolet Monte Carlo SS came in with multiple complaints including the Emissions 1 fuse blowing in the underhood fuse box. Also there were several codes being set in the PCM as a result, P0030, P0036, P0053, P0054 and P0443. All can be related back to the blown Emissions 1 fuse.

Because the Emissions 1 fuse was central to all of the codes I started examining the wiring around both oxygen sensors and the canister purge valve. The wire color involved is pink with a black stripe. Those of you familiar with chasing ignition related shorts on GM vehicles are well versed in the pink/black wires. Always looking for them. Both oxygen sensors had been replaced as well as the canister purge solenoid. The wiring around the O2 sensors looked good and so did the wiring at the canister purge solenoid. Following the wiring harness back from the canister purge solenoid around the top of the engine revealed nothing until I moved the harness a little bit near the alternator. I had left the ignition on and had also replaced the blown fuse. When I moved the harness I saw a flash of light from the front driver’s corner of the engine. A closer look showed some discoloration on one of the upper intake bolt heads.

Looking at the harness from the underside with a mirror and I could see the arc marks in the wiring.

One thing that was a little surprising to me was how rigid the harness had become from engine heat. I already knew the split loom that is supposed to be covering the harness had already crumbled away from a combination of heat degradation and movement.

I separated out the pink.black wire so that it could be protected from shorting out again.

I wrapped the damaged wire and then continued on wrapping the entire harness in the area where the short was found. In most cases I would have wrapped the damaged wire with live rubber tape but given the heat evidence I decided to use a cloth friction tape instead.

I then wrapped the area with plastic electrical tape to better hold the repair together. The adhesive on the friction tape is not that strong initially but it tends to bond together well over time.

I proceeded to remove bits of the remaining split loom from around the top and rear of the engine.

I cut the tape with a razor blade and pulled the reaming pieces of loom out with my fingers and needle nosed pliers.

I slid the new split loom into position inside the taped areas and then re wrapped the areas with fresh tape.

I save various sizes of electrical tape rolls. I use the new rolls in open areas and as they get smaller I set them aside for use later in tight areas. Sometimes I might have ten or mores rolls of tape of all different sizes in the top of my tool box.

In most areas when wires have to be fed sideways out of the loom the factory longitudinal split can be used. In this spot there wire to lead outs on opposite sides of the harness so I had to cut the loom and notch it to accommodate one of them. It can all be re secured with electrical tape later.

You can see the spots where I used tape to secure the ends of the split loom and the area where I had to make room for two lead outs of the main harness.

The customer wanted me to replace all of the missing/damaged split loom in the engine compartment while I had the car in the shop. That was quite a job but it all turned out well. In the next picture the harness looks close to the exhaust heat shield but it is an illusion. In reality there are several inches between the two. As an extra measure against the harness ever shorting out in the original area, I cut a short piece of rubber hose and installed it over the bolt head.

This Monte Carlo had both oxygen sensors and the canister purge solenoid assembly replaced. None of which needed to be. Another reason to stop guessing and start testing.

2004 Cadillac CTS Ignition Will Not Turn Off Completely

This 2004 Cadillac CTS came in with the complaint that the ignition switch would not fully turn off. The engine started and ran normally and could be turned off but the key would stop rotating as if the shifter was still in gear. As a result the battery would go dead.

First things first if the key will not turn all of the way off there is a manual override button that can be depressed as shown below. With the ignition on, depress the button. Then rotate the switch to the off position.

Now back to the problem. I tested the park switch relay function in the Dash Integration Module (DIM). Commanding the solenoid on with a scan tool allowed the key to turn off. This confirmed that the basic switches and wiring were okay. I also looked at data stream to confirm that the computer was seeing the shifter go into the park position and it was. I did note that there was a U1000 code in the DIM. That code means it had lost communication with one of the other modules. My first inclination was that the ECM must be faulty because the 3.6L GM computers have a high failure rate in which this type of ignition switch problem is involved. In my experience other faults are also involved. Including a no crank condition, gauges inoperative, door lock faults, trunk release inop and no reverse lights. The ECM is under the engine trim panel.

It appears like the ECM has been replaced recently. Talking to all parties involved was enough to uncover the answer to this problem. The ECM had been replaced and it was ordered programmed to the vehicle. After it was installed the theft relearn was performed using the 30 minute manual method and the engine started. The customer’s original problem of the a/c compressor relay not working was resolved but now there was this new problem with the ignition key. The original ECM was still available so I reinstalled it. The key problem went away and the original a/c fault returned.

The answer was that the ECM needed to be fully programmed after it was installed on the vehicle. It was only partially programmed by the supplier. In talking with the tech line I found out that only basic programming is done at their facility. They stated that the ECM and programming software need to be able to interact with other modules in the vehicle for the full programming to be completed. I used my Tech 2 scan tool and the GM TIS2Web programming software to complete the programming and all was fixed.

Now, depending on who you are the pre programmed ECM scenario can have positive and negative effects. If you are a DIYer it helps because the vehicle will run and can be driven to a facility such as mine for the full programming to be completed. As long as you know more programming is needed.

If you are a shop and know that a blank ECM needs to be programmed on the vehicle it can throw off the diagnostics when you are told the ECM was already programmed at the factory.

The problem for this vehicle, the owner and myself was that the part store supplier did not properly inform the customer of the need for further/full programming.

2008 Chevrolet Avalanche Right Front Turn Signal Inop

This 2008 Chevrolet Avalanche came in with the complaint that the right front turn signal did not work. This article applies to Avalanche, Escalade, Silverado, Sierra, Suburban, Tahoe and Yukon trucks and suv’s. This generation of GM truck or Suv does not use a turn signal flasher relay as we have always known in the past. Instead the turns signal switch sends a signal to the BCM and and the BCm then sends a pulsing signal to the turn signal bulbs in the front and rear of the vehicle. If the vehicle has turn signals built into the side view mirrors it also sends the same signal to that light as well. If the BCM is at fault for a front turn signal not working check to see if the matching signal in the side view mirror is working. If it is the BCM is doing it’s job and the problem will likely be in the bulb, socket or wiring. This vehicle did not have that option so pinpoint testing was going to be needed. I went ahead and located wiring diagrams and pinout locators for the BCM connectors. Did I mention that I had already tested at the light assembly and the signal circuit was missing. The bulb and socket were okay. Also there were no codes in the BCM data stream and controlling the light with the scan tool produced the same results.

Even though there is not a separate fuse for the right front turns signal circuit I decided to check all of the fuses anyways. This is what I found. The courtesy light fuse in the driver’s side interior fuse box was blown.

Power on one side of the fuse …

… and no power on the other side.

The 15 amp fuse was blown. and is shown below.

Now the turn signal is back working again. In the GM and Mitchell wiring diagrams for the exterior lights/turn signals there is no mention of the courtesy fuse being involved in the turn signal operation. It is shown in supplying power to the BCM though in the power input diagrams. No real reason was found for the fuse being blown but it does have a new radio and other add ons in the cab of this truck. I suspect that the fuse was blown when this stuff was installed. I informed the customer that the fuse may blow again and if it does we will need to look at it again to locate that problem.

Just one more reminder to stop guessing and start testing.