Nov 012017

1999 Chevy Z71

What is the purpose of vacuum line attached to the rear end?

Differential Vent Tube

The vacuum line is a vent tube. This keeps the unit from building pressure internally. It also moves the point of entry above any perceived area of water exposure. For example, Suppose you were to back a boat into the water. The vent tube is positioned high enough not to allow water to enter into the differential that may now be under water.

differential vent tube diagram

Nov 012017

Chevy Impala

Blower motor stopped working

The blower motor stopped working.  I’ve replaced the resister and it’s still not working any suggestions? It is a 2001 Chevy Impala 3.8 series 2.

  • Check the 4 fuses that are used in the blower motor circuit.
  1. A/C Cruise Fuse10A
  2. A/C BLO Fuse(blower) 20A
  3. DIC/RKE Fuse10A
  4. A/C BLO Fuse 25A.

The fuses are located in the inside fuse panel. You may use the wiring diagram to gain a better idea of how the circuit works.

  • Test the blower motor itself. Apply battery positive and negative to the blower directly. I use a power probe to do this. The tool allows you to connect a good ground. And apply battery positive with the touch of a button.

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Blower Motor Wiring Diagram – 2001 Chevy Impala

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1999 Chevy Tahoe engine timing

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Oct 312017

1999 Chevy Tahoe

I just bought a used motor w/137K miles from a junk yard to install in my 99 Tahoe. I was about ready to drop it in when I notice the timing has been advanced 1/4 to 3/8’s of an inch. Does this probably mean what I think it means? The timing chain has probably jumped a tooth and needs to be replaced before I drop the motor in?

Camshaft and crankshaft sprockets

The engine timing is not adjustable. The cam retard offset will not be accurate below 1,000 rpm. What this means is, you cannot check the actual timing without it running. If you are just looking at the timing chain gears and they do not line up dot to dot, then inspect the camshaft and crankshaft sprockets for:

timing gear diagram inspection

  • Broken teeth (1)
  • Damaged teeth (2)
  • Chipped teeth (3)
  • Worn teeth
  • Uneven wear on one edge of the teeth
  • Worn valleys between the sprocket teeth
  • Crankshaft sprocket keyway for wear
  • Crankshaft sprocket woodruff key for wear or damage

2004 Chevy Venture Tail Light Circuit Board Issue

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Oct 272017

2004 Chevy Venture

Tail light problems

I have a 2004 Chevy Venture experiencing issues with the driver side (left) tail light circuit board. The brake light bulb, left turn signal bulb, and reverse indicator bulb aren’t working. Both the top and bottom running light(s) bulbs are working when activated, however when the left turn signal and/or hazard lights are activated, instead of the left turn signal bulb turning on, both the top and bottom running lights flash in sync with the turn signals.

Tonight I’m going to temporarily swap the driver and passenger side tail light circuit boards to see what happens. Any ideas on where the issue might be? Vehicle electronics isn’t my strong suit. Any suggestions and/or advice would be greatly appreciated! It’s my understanding that tail light electrical issues with the 2004 Chevy Venture (and other GM Mini vans from this same generation) are quite common.

This may be the case of installing the wrong bulb or the circuit board is faulty. A 3057 bulb is different than a 3157 bulb. Check this first. You are right that this year vehicle has had its share of tail light problems. The most common fix is replacing the tail light circuit board assemblies.

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Oct 222017

Chevy Equinox

My catalytic converter has melted so says the garage.

Was there a question in there? The converter typically melts internally if there is un-burnt fuel exposed to it during operation. For example, if one of the cylinders of the engine was not firing and allows the fuel to simply pass through. When this happens there is usually a rotten egg smell that accompanies the situation.

Catalytic Converter Replacement (FWD)

catalytic converter 2012 Chevy Equinox

1 Exhaust Manifold Nut (Qty: 3)

Caution: Refer to Fastener Caution.

50 Y (37 lb ft)

2 Exhaust Muffler Nut (Qty: 2)

40 Y (30 lb ft)

3 Catalytic Converter Bracket Clamp Nut

50 Y (37 lb ft)

4 Exhaust Insulator Hanger
5 Seal
6 Gasket
7 Catalytic Converter

Tip: Replace with NEW gasket and seal.

Oct 202017

2000 Chevy Malibu

When it hasn’t been driven for a while and when its cold outside the turn signal stays on and wont flash. Once after quite a few miles and when the engine has warmed up the turn signals work properly and flash when they need to.

This Problem of the Turn Signals on your 2000 Malibu is Due to malfunction of the FLASHER RELAY
The Flasher Relay is Part of the HAZARD SWITCH. Located on the instrument cluster BEZEL.

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The GM part Number is : 22594146

The Best Place for the Flasher Relay COST is aprox. $ 26.00


Oct 202017

Chevy Aveo

My air conditioning quit. The compressor spins, I checked Freon its fine. I put the gauges on it and it read 55psi low side, 100psi high side. Replaced expansion valve and recharged. Same thing.

This is an indication of a restriction in the system. Most likely the condenser is where the restriction is. You can flush the condenser and test for restriction or replace it.

2004 Chevrolet Trailblazer ABS

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Oct 112017

Chevy Trailblazer

My wife’s car has had an abs light on since right after we bought it. I had the codes read. They said it was the wheel speed sensor. I changed out both wheels speed sensors and put brand new brake pads on the front and back as well as new calipers all the way around. She said she drove it today the light still on and it was raining. She was coming to a stop sign and hit the brakes. It made an awful noise and it didn’t want to come to a stop. I have replaced the master cylinder and I have bled the brakes. I have also sanded down all the ground leads and put them back on and sprayed with undercoating as stated. Someone told me it could be the EBCM what should I do or change?

The description of what your wife told you would indicate the ABS was functioning properly. When the roads are wet or icy the ABS motor will activate, making a groaning noise, this prevents the wheels from locking up. When the ABS is activated the light may illuminate temporally and generally goes back off. If the light is on continuously the ABS will not function.

If you want to make sure the ABS doesn’t come and go you can disable the function by removing the ABS fuse or relay. Doing so will allow the brakes to function like all the old cars used to without ABS. Learning to brake a little earlier will help slow the car and also cause your brake pads and rotors to last longer. You can drive the car this way as long as you like but the ABS light will remain on.

If you want to repair the ABS system the use of a scan tool will be required for individual testing of components.

Antilock Brake System (ABS) Warning light

With the Anti-Lock Brake System (ABS), this light will come on when you start your engine and may stay on for several seconds, that is normal.

A chime may also sound when the light comes on.

If the light stays on, or comes on when you are driving, your vehicle needs service. When the regular brake system warning light is not on, you still have brakes, but you do not have anti-lock brakes. If the regular brake system warning light is also on, you do not have anti-lock brakes and there is a problem with your regular brakes. See Brake System Warning Light earlier in this section.

The ABS warning light should come on briefly when you turn the ignition key to RUN. If the light does not come on then, have it fixed so it will be ready to warn you if there is a problem.

Antilock Brake System

When wheel slip is detected during a brake application, the ABS enters antilock mode. During antilock braking, hydraulic pressure in the individual wheel circuits is controlled to prevent any wheel from slipping. A separate hydraulic line and specific solenoid valves are provided for each wheel. The ABS can decrease, hold, or increase hydraulic pressure to each wheel brake. The ABS cannot, however, increase hydraulic pressure above the amount which is transmitted by the master cylinder during braking.

During antilock braking, a series of rapid pulsations is felt in the brake pedal. These pulsations are caused by the rapid changes in position of the individual solenoid valves as the EBCM responds to wheel speed sensor inputs and attempts to prevent wheel slip. These pedal pulsations are present only during antilock braking and stop when normal braking is resumed or when the vehicle comes to a stop. A ticking or popping noise may also be heard as the solenoid valves cycle rapidly. During antilock braking on dry pavement, intermittent chirping noises may be heard as the tires approach slipping. These noises and pedal pulsations are considered normal during antilock operation.

Vehicles equipped with ABS may be stopped by applying normal force to the brake pedal. Brake pedal operation during normal braking is no different than that of previous non-ABS systems. Maintaining a constant force on the brake pedal provides the shortest stopping distance while maintaining vehicle stability.

Programming the Traction Control Automatic Engagement Feature

The automatic engagement feature may be programmed so that the traction control system activates or does not activate automatically at the start of each ignition cycle. In order to change the status of the automatic engagement feature, perform the following procedure:

Important Failure to follow the correct procedure may cause DTC C0283 to set in EBCM memory.

  • Park the vehicle and apply the parking brake.
  • Unlock the ignition and shift the transmission into NEUTRAL (N).
  • Turn the ignition ON, engine OFF.
  • Press and hold the brake pedal and the accelerator pedal.
  • Press and hold the traction assist switch for 5 seconds.
  • Release the brake and accelerator pedals and the traction control switch.
  • Turn the ignition OFF.

Brake lines 2000 Chevy Impala

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Oct 092017

2000 Chevy Impala

My 2000 Chevy Impala LS 3.8 motor brake lines are shot. Wondering how much it’s going to cost me to replace them. I believe it’s only the front ones.

Brake line Cost

If you are referring to the brake hoses that attach to the calipers it shouldn’t take more than a hours worth of labor. Around $100 plus parts and tax of course. The labor guide does not reference replacing the brake lines and will normally be charged by the hour for how ever long it takes. I wouldn’t think any longer than a couple of hours plus parts.

Oct 052017

1994 Chevy Corsica

I have a Chevy and it starts up but when you put in gear it stalls would it be the starter or something else?

Something else. The starter is used to “start” the engine and is disengaged once it starts.  The most common cause for this would be the TCC Torque Converter Clutch solenoid. In most cases if you can unplug the TCC solenoid (5 in diagram) at the transmission and the stalling issue will go away. However the converter will no longer lock up. This will leave you with the impression that you no longer have overdrive. Rest assured, you can drive the car this way for as long as you would like or until you decide to drop some serious coin and have it fixed.

TCC Solenoid location diagram 1994 Chevy Corsica

The TCC Solenoid

The TCC solenoid is what actually causes the TCC to engage and disengage.

When the TCC solenoid receives a signal from the ECM, it opens a passage in the valve body and hydraulic fluid applies the TCC. When the ECM signal stops, the solenoid closes the valve and pressure is vented causing the TCC to disengage. If the TCC fails to disengage when the vehicle comes to a stop, the engine will stall.