2003 Toyota 4Runner, Battery Corrosion

This 2003 Toyota 4Runner battery post is a perfect example of why you should look under your hood and inspect things on a regular basis. It does not take long for a battery terminal to get corroded. Also with corrosion this bad something else is going on. For some reason there is battery acid leaking near this battery post. A good clean up is needed. Of course you can use baking soda and water as we have all been told to clean this up. I use a purple degreaser in a spray bottle and it works quite well. You have to use a base or alkaline solution to neutralize and acid. The standard purple degreaser is an alkaline solution. Remember though that in the process of neutralizing an acid with a base that a salt is formed and metals do not like salts. Be sure to rinse thoroughly.

A good soaking with the alkaline degreaser along with a thorough rinsing and the terminal is quite clean. You can also see the reason for the corrosion. See the splits in the plastic case around the battery post.

Luckily there was no damage to the battery cable terminal end.  A new battery and a little more cleaning and this one was done, except for the a/c repair I still have to do.

2004 Cadillac CTS No Stoplights

This 2004 Cadillac CTS came in with the complaint of no stoplights. I decided to start by checking the bulbs. To do this I first had to remove the black plastic nuts that also serve as hooks for the cargo net.

After the nuts were removed I pulled the trim panel up that goes across the lower lip of the trunk. This had to be done in order to pull back the side panels.

With the side trim panels pulled loose and out of the way, I could now reach my hand around and remove the two 10 mm nuts that hold the light assemblies in the car.

This is a picture of the holes in the rear fender that the light attaches to. Sorry, there was no room for a picture from the inside.

The studs that attach the light to the car.

The upper socket is for the stoplights and on this car it was grey in color.

If you look closely at the bulb you will see the stoplight element is laying in the bottom of the bulb instead of being attached to the shorter leads.

Another picture of the bulb showing that the shorter or lower element is missing.

The side stoplights were simple enough. Now on to the CHMSL (center high mounted stoplight). I removed the retainers on the left side of the trunk lid trim panel.

Moved the panel out of the way far enough to access the wiring and tested for power on the white wire while the brake pedal was depressed. I had power.

In looking at the wiring diagram I noticed that the CHMSL and the tag lights share a common ground. A quick check of the tag light operation showed that the ground was present in the truck deck lid. Diagnosis of a faulty light assembly. I checked on a replacement light and found that the $668 list price was too much for the customer to handle at this time. I don’t blame them.

Anyways I guess two stoplights are better that none.

1998 Chevrolet Lumina, Battery Goes Dead Again

This 1998 Chevrolet Lumina had been in a few weeks back for a complaint of the battery going dead. I had located and replaced a faulty driver’s side power door lock switch. The customer called and stated that the battery had gone dead again and wanted to know if I would look at it. I asked if the door lock still worked and she said no. When the car arrived the first thing I looked at was the driver’s power door lock switch to see if it was okay. It felt okay but the door locks did not work, so I checked the passenger side switch. We got a problem!

The switch would not move. I removed the retaining screw from the trim plate and pulled the trim plate off of the door. The front edge is held in place by a spring clip.

I unplugged the switch and waited about five minutes for the power door lock circuit breaker to cool down. I checked the driver’s side switch and the system was back to working.

I informed the customer that the passenger side switch had failed and asked if she would like to replace it or leave it unplugged. She said replace it so I did.

You can see the position of the old switch is not centered. It was stuck in that position.

1997 Chevrolet Suburban, Cruise Control Inop

This 1997 Chevrolet Suburban came in with the complaint that the cruise would work sometimes. This repair applies to multiple Chevrolet and GMC trucks and vans that use the cruise servo number 25315088, gasoline only, no diesels. For a list of these vehicles please go to the ACDelco website and you will find a tab labeled “Vehicle List”. Enter the part number there it will open up a list of vehicles that this part and repair apply to.

The cruise control servo is located under the hood on the driver’s side of the vehicle. It is between the master cylinder and the driver’s inner fender panel. You will need a voltmeter for this test. Preferably one that will read frequency or hertz. After disconnecting the harness connector you should notice that there are letters on the side of the connector body as shown below.

I use a test lead with the correct size terminal on the end. If you use just the meter test lead, use a very gentle touch. If you press too hard you will distort the terminals and render the connector useless. The picture below shows the meter connected and a nominal battery voltage reading.

  • A Cruise On/Off Switch,Grey, 12 Volts
  • B Set/Coast Switch, Dk Blue, 12 Volts
  • C Resume/Accel Switch, Gry/Blk, 12 Volts
  • D Brake /Clutch Pedal, Purple Or Brn/Wht, 12 Volts Key On, O Volts Pedal Depressed
  • E Ground, Blk/Wht, 12 Volts Checked to Battery Positive
  • F Cruise Fuse #6, Brown, 12 Volts Key On
  • G Brake Applied Input,White, 12 Volts Pedal Depressed
  • H Blank/Sealed
  • J Cruise Status, Lt Blue, 12 Volts from VCM/Computer, .125-.350 Volts With Cruise Engaged, The Cruise Module Pulls The 12 Volt Signal Low
  • K Vehicle Speed Input, Dk Grn/Wht, O, 4.5 or 9 Volts as Rear Wheels Turn With Key Voltage Fluctuates

All of the test signals on this vehicle were good. Diagnosis of faulty cruise servo. There are three screws that hold the servo in place. Two on the right side if the picture and one on the left behind the electrical harness connector, where testing was done.

Once the module/servo is unbolted the the retaining tabs for the throttle cable can be depressed and then the cable can be pulled out with a rocking motion. It can be a little difficult as there is an o-ring that may have to be persuaded to come loose.

Once the main cable is pulled loose from the module/servo there is basically a ball and hook that have to be disconnected.

Note here that the end of the cable connected to the throttle linkage has to be disconnected in order to remove the ball from the hook.

2000 Chevrolet Silverado, Changing The A/C Belt

This 2000 Chevrolet Silverado came in with the complaint that the a/c was not getting cold. A quick visual inspection found that the a/c belt was gone. Most owners do not even realize there is a separate a/c belt. In order to replace the belt, the primary serpentine belt has to be removed. This requires removing the air intake tube.

Loosen a hose clamp at both ends.

Disengage the radiator hose clip from the tube assembly.

Pull the hose assembly from the vehicle.

Locate the belt tensioner assembly and using the tool of choice release the tension from the main belt.

A different view. I use a special wrench kit made for belt adjusters but a wrench or ratchet and socket will work also. The longer the better though. Leverage makes a difference.

With the tension released, the main belt can be removed.

Next the front gravel plate needs to be removed. Three bolts on the upper edge and two on the lower.

Position the main belt out of the way.

Install the new a/c belt. It is a little tedious but I install the belt over the crank pulley first and let it go past the rear of the pulley. Then put the belt on the compressor. Adjust the tensioner pulley and pull the belt back onto the crank pulley. Reassemble and it is done.

As a footnote many times that the belt will be missing or found to be burnt on half, the compressor is locking up and will have to be replaced. That is a whole different story though.

2002 F150, P0401 Insufficient EGR Flow

This 2002 Ford F150 with a 5.4 liter engine came in with the service engine soon light on and a P0401 code stored. This same general test applies to most Ford, Lincoln and Mercury vehicles with EGR valves and DPFE sensors. Wire colors may vary and you may wish to consult a wiring diagram. It is easier to access the EGR valve and the DPFE sensor with the throttle body cover removed so I started by doing just that.

After I removed the cover I saw the problem. The two hoses that connect to the DPFE sensor were disconnected. I hooked the hoses back up and decided to do some testing to show how to test this system as I get many requests. Testing is as follows: The brown/white wire is the 5 volt reference voltage from the computer to the DPFE sensor. The grey/red wire is referred to as the signal return (it is a ground signal from the computer). The brown/light green wire is the actual DPFE sensor voltage sent to the computer from the sensor. All pinpoint testing must be done with a quality voltmeter. Do not use a test light on computer circuits unless specifically directed in repair information. With the key on the brown/white wire should have a nominal 5 volts. The grey/red wire should have near zero volts when checked from chassis ground to this wire. It should have near battery voltage when checked from battery positive to the grey/red wire. Be careful to not damage the wires.

The brown/light green wire should have between .5 and 1 volt when checked to chassis ground with the key on and engine off. The voltage should remain the same with the key on and the engine running and no vacuum applied to the EGR valve.

The voltage should increase as vacuum is applied to the EGR valve on a running engine. The follow picture shows that the vacuum applied to the EGR valve is about 22″ and the voltage is close to 3 volts. The engine should also start idling poorly and possible stall when vacuum is applied. The following are key points if you do not want to replace parts needlessly!!! If the engine idle does not change, the voltage remains low, the EGR valve holds vacuum and you can see or feel the pintle shaft move. DO NOT REPLACE THE EGR VALVE. It is not the problem. Instead the EGR ports to the throttle body are restricted and need to be cleaned. I hope to do a post on this soon, just waiting for one to come in. Now, if the idle does change as described above, the signal voltage does not and you have confirmed sensor reference and ground circuits are okay, then the DPFE sensor is faulty or there is a problem with the hoses as in my case with this truck. The only time the EGR valve should be replaced on these vehicles is if the valve will not hold vacuum or the pintle will not move when vacuum is applied or released. As of this writing I have never replaced an EGR valve on a Ford vehicle to correct and insufficient EGR Flow Code.

The following is just scan data that can easily be watched while test driving. One could extend the voltmeter leads to the inside of the vehicle and do the same test while some one drives the vehicle.

Be sure to follow proper safety procedures as testing requires the engine to be running. Mistakes can be tragic and fatal to both you and others.

2004 Buick Rendezvous, Turn Signals and Hazard Lights Inop

This 2004 Buick Rendezvous came in with a complaint that the turn signals and hazard lights would not work. The customer stated that the problem occurred shortly after backing a boat in the water. I started by checking to see which fuses were involved and located the fuse box on the passenger side of the center console.

While I am here I decided to point out the flasher unit (turn signals and hazards)

Fuse number 19 for the turn signals.

Fuse #40 for the hazards. The fuse was blown and replacing it brought all of the lights back to work. Apparently the flasher is set up so that if the hazard fuse blows you will lose both hazards and turn signals.

Since the customer had mentioned about backing a boat trailer, I decided to look at the harness for the trailer. Pretty clear to see why the fuse blew. The green wire is for right turn and stoplight. The white wire is ground.

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2000 Chevrolet Silverado, Changing The Cabin Air Filters

This 2000 Chevrolet Silverado came in with a complaint that there was not much air coming through the vents. The customer said he thought the blower motor might be worn out. A quick look under the dash and I saw that this truck has a cabin air filter. I removed the single screw at the rear of the filter cover.

Lowered the rear edge and swung it down to release the hinge point (hook).

I started pulling the filter out and this is what I found. After sliding the first filter out, I had to pull the second filter towards me first and then pull it down.

I cleaned all of the loose debris from the hole and started putting the new filters in. First I slid it straight up and then pushed it towards the front of the truck. Installed the second filter and this one was done.

These are the old filters after I had knocked the heavy debris off.

1997 Audi A4, No Headlights

This 1997 Audi A4 came in with a complaint of no headlights. I looked at the diagrams and it looked pretty simple. First I had to get to the wiring at the back of the headlight combination switch. There are four screws that hold the lower dash cover in place. Two behind the insert strips on either side of the steering column. One at the lower right corner of the panel and one at the lower left end of the panel, behind the fuse cover.

With that out of the way I found a couple of screws that hold the upper steering column cover to the lower. They would be slightly higher up in the picture if I would have gotten them in this picture. The screws shown are for the tilt handle and the lower cover. I removed all of the screws and found that the lower steering wheel cover would still not come off.

To get to the remaining screws the steering wheel had to be removed and therefore the airbag/srs system had to be disabled. The repair manual stated to disconnect and shield the negative battery cable and wait several minutes before working on the system. I usually wait at least fifteen minutes if unsure. Then I proceeded with disconnecting the airbag harness connector. It is the red connector in the picture and can be found on the left side of the steering column.

Next I removed the retaining bolts that held the airbag  to the steering wheel. With the air bag removed I took off the retaining nut, marked the steering wheel position in relation to the shaft. The engineers on this car over designed the steering column cover mounts and under designed the steering wheel to shaft alignment.

Anyways with the steering wheel out of the way I could now remove the three screws that still held the lower column cover in place.

One more engineering marvel.

The lower cover will not come off due to a trim piece that is still connected to the dash.

There are two phillips headed screws, one on either side that have to be removed along with some lower screws not pictured.

Now with the cover finally removed I could access the clamp bolt in the rear of the switch assembly.

Finally the switch is out of the way so I can start testing.

This is where I made a slight error in judgement. I assumed, as virtually all other vehicles in this country will clear an airbag code after the fault is corrected, that this one would too. Wrong,Wrong, Wrong. I reconnected the battery in order to test the headlight circuit. I located the wiring terminals as identified in the following pictures.

Jumped them together with a fused jumper wire and the headlights worked. Successful diagnosis of a faulty headlight switch.

I removed the screws that held the two halves of the switch together and pulled them apart.

Slid the new switch into the existing old switch and joined them together and reassembled the car.

I was happy to finally have this car done but what is this the airbag light will not go off. Checked to make sure all connections were good and consulted my repair information to see how to clear the code. I knew I set a code when I tested the headlight circuit but most other cars self clear airbag codes after the fault is corrected. Repair information stated that a scan tool is required to turn  off the airbag light. Okay, got mine out and found that the system was recognized by the scan tool but it would not communicate with the air bag system. Well to make a long story reasonably short, I did a ton of research and called several friends in the business and finally found one with a scan tool that could clear the codes. If I ever have to do one of these again I will do one of two things. I will make sure my scan tool will communicate with and clear airbag codes or I will test the switch to make sure it does not complete the circuit for the headlights instead of testing the vehicle with the battery hooked up as I normally would.

2000 Ford Windstar, Changing The Driver’s Power Window

This 2000 Ford Windstar came in with a driver’s power window inop.  I did  a quick test and found that the motor was bad. The quick test consists of turning the key on with the engine off. Then move the switch for the window in question up and down. While doing this look at the lights on the dash. If they dim slightly with each push of the switch it quickly confirms that the motor is getting power and ground in both directions. If it only dims in one direction more than likely the switch is faulty.

Anyways I knew the motor was faulty so I started removing the door panel. First I lifted the switch panel from the door. Hopefully you can see the spring clip that holds the panel to the door.

Next I pulled the interior handle trim plate out of the door. Pry the forward edge out and then slide the whole thing forward.

There are two 7 mm headed screws at either end of the interior pull handle.

There are two more screws along the lower door panel edge.

Next I unsnapped the upper triangle shaped cover from the door.

One more screw behind that panel.

Now the panel will slide up and off of the door.  Make sure to disconnect the courtesy light from the panel.

Carefully remove the the foam insulated moisture barrier from the door. Just pull it a little at a time until it pulls loose.

Now we can see the motor, kind of. The red and yellow wires connect to the window motor. The nut is one of the fasteners for the motor and the other two bolts are behind the metal panel. Thankfully Ford almost always puts dimples in the panel to let mechanics know where to drill in order to remove the screws.

I started with a small drill bit and worked my way up to a half inch bit. The hole needs to be large enough for a 5/16″ or 8 mm socket to go through.

The holes are now large enough and I have removed the two screws. Next I removed the nut.

Then I loosened the stud so that the motor would come free. The stud stays in the hole.

The stud has a torx head as shown below.

I lined the stud up with the appropriate hole in the replacement motor and snugged it up. I left it loose enough so that I could rotate the motor around to line up the other two screw holes.

With everything back in place I vacuumed the metal shavings out of the inside of the door and sprayed some paint on the exposed metal.

DSC01897

I put the remaining parts back on in the reverse order.