1997 Infiniti Q45 Poor Acceleration,Surging Idle And Service Engine Soon Light On.

This 1997 Infiniti Q45 came in with the complaints of poor acceleration,surging idle and the service engine soon light on. I checked codes and found 9 codes stored. I knew that most were probably induced or false codes so I cleared the codes and then ran the engine till the SES light came back on. It did not take very long. The only codes that returned were for and open Intake Air Temperature sensor (IAT) and P0100, open or shorted Mass Air Flow sensor (MAF)

I found the IAT sensor harness disconnected. you can see it in the picture above and you can see it in the picture below after I had reconnected it. That part was simple.

I next focused on the MAF sensor. It is located between the air filter box and the engine air intake tube. It is shown below with the air filter and cover assembly removed and also with the connector removed.

The test for the sensor is pretty simple. Check the voltage on terminal #1 (white wire) with the key on and the engine off; less than 1 volt, Key on/engine running;1.0-1.7 volts, Engine running between idle and 4000 rpm; Varies between 1 and 4 volts. If the voltage readings are within specifications then the white wire will need to be checked between the MAF sensor and the engine control computer. On this vehicle I found the reading at 0 volts so I continued checking the input power and ground circuits to the sensor by disconnecting the harness connector and testing for power on terminal #3 (red/green wire) and ground on terminal #2 (black wire) with the key on and the engine off. I had both so the diagnosis is a faulty MAF sensor.Testing terminal #1 (white wire) should only be done with a voltmeter and I strongly recommend testing all sensor wiring with a voltmeter.

To replace the MAF sensor, the breather assembly will need to be removed. I started by unhooking the spring latches.

Then I removed the hold down bolt and pulled the cover and filter off.

I finished removing the lower hold down bolts and disconnected the air intake hose from the MAF sensor.

Next, I removed the two retaining nuts and removed the sensor. I then reassembled the air filter assembly in reverse.

The picture above shows the sensor elements within the MAF sensor. If the vehicle would have had lean run codes, this would have been a good place to look for the problem. Over time, lint from the air filter will build up on the elements and leave a very light covering over the sensor and this will cause the sensor to give a false reading to the engine control computer. After finding the build up I will take a very small screwdriver and very lightly rub the lint film from the sensor elements.

1984 Toyota Pickup Charging System Over Charges

A customer brought in a very clean 1984 Toyota Pickup with only about 65,000 miles on it with an over charging condition. The alternator had already been replaced.

The customer had tried a new voltage regulator with no change in the over charge condition.

I tested the wires at the voltage regulator and found that there was no power on the battery sense terminal (White) going to the regulator. I had power on the ignition feed wire (Red) and also on the charge light wire (Yellow).

I back tracked to find the open circuit. I checked the connector near the regulator and there was no power there either on the smaller white wire.

I went to the connector, behind the driver’s side headlight and I had no power on the regulator side of the connector.

I checked the battery side of the connector and there was power present. I tried to pull the connector apart to inspect it for damage but it was melted together.

I knew that I would not be able to find a new connector and that it would take a while to find a used one. After consulting with the customer, we agreed to cut out the faulty connector and splice the wires back together. I cut the wires as close to the connector as possible and by doing so I was able to splice them directly together without having to add in extra wire.

Of course, I used quality, seamless, non insulated butt connectors and dual wall heat shrink tubing.

After melting the heat shrink tubing into place, I wrapped the harness with tape to finish the repair.

I rechecked the wiring to the regulator and the signal was back. The system is now charging properly

Turn Signal Fuse Blows In 1997 Chevrolet Suburban

This Suburban came in with the complaint that the turn signal fuse blows. The customer could not relate when the fuse would blow and it would not blow when it came in the shop. I first went to the rear and and inspected the wiring there and found no problems. Next I turned my attention to the front of the Suburban.

I removed the front turn signal / park light assemblies and there it was. I did not really surprise me though because it is such a common problem in this series of trucks. Although normally the park light fuse is the one that has the problem. The following picture shows where the wires had been rubbing (rust spot).

You can see the rust transfer onto the wires in the following picture.

After cleaning the wires it is very clear where the light blue turn signal wire was shorting to ground. The brown park light wire was undamaged and the black ground wire was slightly rubbed but not shorting. I cut and spliced the wire back together using a piece of dual wall heat shrink tubing to cover the splice.

1999 Pontiac Grand Prix Code P0125

This 1999 Pontiac Grand Prix came in with the Service Engine Soon Light on (SES) and a code P0125. The code refers to an engine coolant temperature excessive time to enter closed loop fuel control fault. Simply put the engine did not come up to operating temperature as quick as the computer thought it should. Testing is pretty simple. Make sure the system is full of coolant. Start a cold engine and see if the upper radiator hose warms up quickly. If it does the thermostat is stuck open and not allowing the engine to build heat. Sometimes it is as easy to drive an already warm vehicle and watch the gauge if present or in my case observe coolant temperature in data stream. If it fails to reach and maintain between 185 and 195 again the thermostat is stuck open. The next step of course was to change the thermostat. It is located in the very convenient position of under the throttle body and behind the exhaust crossover pipe. This procedure applies to most of the General Motors Vehicles with the 3.1 liter and the 3.4 liter engines with the thermostat hidden in the same place. The first thing I had to do was to drain the coolant level. The radiator drain is at the bottom of the radiator, driver’s side, on the engine side of the radiator. I was able to loosen the drain by sliding my hand between the engine and the fan assembly to reach the drain and loosening it with a 1/4″ ratchet and short extension. I let the coolant drain into a pan. One could of course gain access from the bottom of the vehicle as well.

After the coolant had started draining, I next removed the air inlet hose. This required disconnecting the intake air temperature sensor and the mass air flow sensor electrical harnesses. The crankcase ventilation tube also had to be pulled from the rubber hose. I also remove the air filter and filter cover for more elbow room.

Next I removed the throttle cable bracket and unhooked the cables from the throttle body.

With that out of the way I closed the drain on the radiator and removed the upper radiator hose from the thermostat housing.

I then went to disconnect the coolant lines that go from the heater pipe to the throttle body. I found them to be very soft. I decided that I would be replacing them so I cut them rather than remove them. I remove the heater hose at the rear of the pipe and removed a hold down nut at the front valve cover. Now here is where it gets a little tricky. many manuals say to remove the exhaust crossover pipe and in some cases I have had to but most of the time I can remove the top bolt with ease.

And then using a wrench I can slide it under the crossover pipe, place it on the bolt head and break the bolt loose.

Sometimes I have to break it loose from the top. Which ever way works best. Once it has been loosened a couple of turns I can usually unscrew the bolt with one finger from the top and one finger from underneath. I try not to remove it completely. Instead I back it out most of the way and keep working with the thermostat housing until it will come out of the hole. The housing is slotted for this purpose. If I do take it all of the way out I simply reinstall it prior to replacing the thermostat. About two threads is all that is needed.

I try to pay attention to the position of the thermostat so that I can install the new one exactly as the old one. This makes it easier to install the housing.

The new thermostat is set in place ready for reassembly. When replacing the small coolant hoses at the throttle body be sure to cut the new ones to the exact length of the old ones or you will have to remove and reinstall again.

2002 GMC Envoy No Low Blower Speeds

This 2002 GMC Envoy came in with the complaint of the two lowest blower speeds missing. Because one of the lower speeds worked along with the high speed I knew that both fuses were good and I went directly to the blower resistor which is very prone to failure. The blower resistor and the blower motor are both located on the passenger side of the vehicle. By the way, this repair applies to 2002-2009 Chevrolet Trailblazer and GMC Envoy, 2004-2007 Buick Rainier and 2003-2008 Isuzu Ascender models.

First I removed the lower dash trim panel by removing the two attaching screws.

The blower motor is to the right side.

The blower resistor is slightly to the left of the blower motor and towards the firewall.

Next I removed the connector at the blower motor. Using a small screwdriver from the underside of the blower motor, I depressed the retainer.

With the retainer released, I pulled the connector from the blower motor.

A side view of the blower motor and connector.

A view of the connector retainer that has to be depressed.

I next disconnected the seven wire connector to the blower resistor, removed the two attaching screws and removed the resistor assembly.

Here is a look at the old style resistor.

And the new style replacement resistor. To order these parts please click here.

I reversed the procedure and all tested okay. Normally I would have replaced the harness connector as part of the repair. However since there was no damage and the customer insisted on not replacing it I did not. Hopefully it will not burn out very soon. It is documented on the repair order that the customer declined the repair and therefore there is no warranty.

Actual testing of the wiring is as follows. Disconnect the 7 wire harness connector and inspect. If there is any sign of heat damage replace both parts per above instructions. If there is no sign of heat damage then check the following. With the 7 wire harness disconnected check for power on the red wire. It should have 12 volts at all times and it gets it’s power from the 40 amp blower fuse in the under hood fuse box. Next with the key on check for 12 volt power to each of the following wires as you move the blower speed switch from low to high. Yellow / low, tan / med 1, lt blue / med 2, purple / med 3 and orange / high. If any of these signals are missing you will need to inspect the HVAC fuse in the interior fuse box ( under rear seat, driver’s side). If the fuse is okay you will need to check the blower speed switch.

  • Terminal “A” Tan = Speed 2, power through blower switch from HVAC fuse
  • Terminal “B” Yellow = Speed 1, power through blower switch from HVAC fuse
  • Terminal “C” Purple = Speed 4, power through blower switch from HVAC fuse
  • Terminal “D” Lt Blue = Speed 3, power through blower switch from HVAC fuse
  • Terminal “E” Black = Blower system, ground at all times
  • Terminal “F” Orange = Speed 5, power through blower switch from HVAC fuse
  • Terminal “G” Red = Speed 5, Constant power from BLWR fuse under hood

If all of the tests above are okay and you want to go a step further, place a test light or voltmeter in the wires going to the blower motor. If the light comes on or you have a 12 volt reading, the resistor and wiring are okay and the blower motor is faulty. This can also sometimes be confirmed by bumping the blower motor with the switches on. If the motor starts after bumping the motor is faulty. One can also remove the blower motor and apply 12 volts (power and ground) directly to the motor. Be careful though the motor will tend to jump and roll all over the place. Hold it firmly and be sure you are clear of the impeller as it could hurt you pretty easily.

One other note. If you have an amperage gauge, test the blower amperage draw while it is mounted in the blower case. Turn on surge amperage could go up to about 28 amps. Amperage draw at high blower should be in the 18 to 24 amp range. The lower the better. Restricted cabin air filters (if present) and dirty evaporator cores will cause a blower motor to draw more current while reducing air flow volume. These two conditions combined will significantly reduce the life of any blower resistor.

2001 Chevrolet Silverado With No Stoplights / Brakelights

This 2001 Chevrolet Silverado came in the shop with the complaint of no stoplights. First I confirmed that none of the stoplights were working including the CHMSL (center high mounted stop light). After this I went to the underhood fuse box because the manufacturer has made diagnosing the stoplights very easy at this location. By going to the red, 10 amp, vehicle stoplight fuse, #17 and checking for power while some pushes on the brake pedal I can tell easily if the stoplight switch is good and I do not have to lay under the dash to do it. I identified the fuse location using the legend.

This one was really easy because when I located where the fuse was supposed to be I found that it was missing. I installed a new fuse and tested both sides for power while someone depressed the brake pedal. I found that the owner had been swapping fuses trying to keep his power outlet working for his cell phone charger.

If I had found power on one side of the fuse but not the other it would have indicated a blown fuse. If I had found no power on either side with the brake pedal depressed I would have suspected a faulty stoplight switch or no power to it and more testing would have been needed.
Luckily, the power supply fuse for the stoplight switch is the yellow, 20 amp fuse, #14 is right above the fuse I was testing. Testing here would have shown one of two things. Power on fuse #14 with no power on fuse #17 would indicate a faulty stoplight switch. If fuse #14 had been blown it would have indicated a short between the fuse and the stoplight switch and back to fuse #17. Also a blown fuse #17 would indicate a short between the fuse and the rear of the truck.

1990 Ford F150 Pickup Truck,Changing The Ignition Lock Cylinder And Keys

This repair is similar for many of the Ford trucks and vans of this era. It is very simple to do as long as the key will still switch on and the electrical portion of the ignition switch is properly adjusted. First switch the ignition on and locate the access hole for the release pin. Then using a small rod, push in on the retaining pin. You should feel it move in about an 1/8″ of an inch.

Once the pin is pushed in simply pull on the lock cylinder assembly and remove.

To install line up the notches and push the new cylinder back in and turn the key off.

If the pin pushes in but the lock cylinder will not pull out, you may have to loosen the electrical portion of the ignition switch located further down the column. I had to do this in order to remove this one and yes, I realise that I am showing pictures of removing and installing the same new lock cylinder in all of the pictures. Just the way it works out sometimes.

If you have to get to the electrical portion of the ignition switch, it is located above the aluminum plate show in the picture. Remove the 6 bolts holding the bracket on and the steering column will drop down and you will find the switch on the left side of the column. It is held in place by two nuts.

1990 Ford F150 With No Low Or Delay Wiper Speeds.

This 1990 Ford F150 came in with several problems among which was the complaint of no low and no intermittent wiper speeds. Luckily I had to inspect the headlight switch anyways so I got to kill two birds with one stone.

The first step was to remove the headlight and wiper switch knobs. I had to slide a small screwdriver blade into the slot and depress the retaining clip and then pulled the knobs off.

Next I removed the lower dash cover.

I then grasped the edge of the switch trim panel and pulled it towards the seat to release the spring clips.

I also removed the right trim panel for some other work that I would be doing. For that I removed the one screw on the left side of the steering column that is normally covered by the left switch trim panel.

I removed the screws that held the switch mounting plate to the dash. I disconnected the red connector at the rear of the wiper switch. I then disconnected the black plug in connector that is further back in the dash. After that I removed the one screw that holds the mounting bracket for the delay module and pulled the module out of the dash.

I dis assembled the module by removing the two screws and pulling the circuit board out of the plastic case. Sorry for the lack of pictures on this step.

I located several cracked / broken solder joints. After cleaning and resoldering I put the system back together and all is well. If you will click on the image to enlarge it you can see the faulty joints in the bottom right corner.

1990 Ford F150 Pickup, No Headlights

This 1990 Ford F150 Pickup came in with a complaint of the headlights work sometimes and sometimes they do not.

The easiest place to start is at the headlight switch on this truck. the first step is to remove the headlight and wiper switch knobs. There is a slot in each one of the in which you have to depress the metal spring latch and pull the knob from the shafts.

With the switch knobs removed I next removed the lower dash cover. It is held in place by four plastic zeus type twist locks. This one had the electric brake controller attached so I just let it hang in place rather than disconnecting the wires.

Next I grasped the trim panel and pulled it towards the seat until it unsnapped and released.

I had some more things to repair on this truck so I went ahead and removed the trim panel on the right side of the steering column. There is one screw that is hidden under the left panel and then it pulls off just like the other. After that I removed the three of four screws that hold the switch plate in place.

I pulled the switches out and this is what I found. The Red/Yellow wire which is the power supply out to the dimmer switch and then to the headlights was burnt.

Time to install a new Motorcraft headlight switch SW6352 and The Electric Connection repair harness #4000 . To order this repair harness please click here. Next I had to remove the nut that retains the switch to the mounting plate.

With the nut removed I pulled the switch from the mounting bracket. I then flipped the switch over to reveal the release button for the pull handle shaft.

I pulled the shaft out until it reached its stop and then pushed in the retaining button and finished pulling the shaft from the switch.

The next step was to release the retaining ears on the harness connector. I had to pry them away from the switch while pulling the harness connector in a rocking motion to fully release the connector from the switch.

The connector looked even worse from the switch side.

I started switching the good old wires from the original connector to their corresponding locations in the new connector. The terminal locks can be released with a paper clip, small screw driver or a terminal tool. I then cut the remaining wires from the old connector.

Once the old connector was out of the way I could pull and adjust the wire length to the proper position for the wire to lay flat in the harness.

After cutting the new and old wires to length I cut and additional 1/4 inch from the longer wire. This makes up for the extra length that comes into the wiring when the splicing connector is installed.

After the terminal and heatshrink tubing was in place I proceeded to splice the remaining two wires. The wires had not been damaged but it is so common for the park light wires to burn out in this type of system I decided to go ahead and do some preventative maintenance for the customer.

I also staggered the spliced joints so that the harness would not have a large knot in it that could cause other problems.

I taped the harness back up and reassembled the dash.

On to the next problem.

1987 Dodge Dakota No Charge Condition

This 1987 Dodge Dakota came in with the complaint of the battery going dead while driving. After checking the system at the battery with a volt meter and amp meter, I went to the voltage regulator on the firewall to start testing. I don’t get a chance to work on something this simple very often and it was kind of fun. First I disconnected the regulator with the key on and checked for ignition power on the dark blue wire and it was present.

Next I checked for bleed through power on the green field wire and it was not present. These connector sometimes burn out. To order a replacement harness please click here.

I then checked the wires at the alternator. Power was present on the blue field wire.

Voltage was also present at the main battery post on the rear of the alternator.

Again there was no bleed through power on the green field wire.

Time to remove the brushes for inspection.

Sure enough the brushes were worn out.

Now for some charging system basics. The charging systems on Chrysler, Dodge and Plymouth vehicles from the early 70’s to the late 80’s used alternators with brushes that were completely insulated from chassis ground (sometimes referred to as above ground). An ignition power signal was sent to one of the brushes and to one terminal of the voltage regulator. The second terminal of the regulator sent a variable ground signal to the other brush. Both brushes connect to the rotor slip ring which are then connected to the field wire wrapped around the internal core of the rotor. As the regulator is the end termination of the field circuit, If the field circuit is complete through the wiring and the alternator I should of had power at both terminals of the regulator connector with the regulator unplugged. I did not have power on both and that is why I proceeded to the alternator for more testing.