Why does my GMC heater not work on high?

Why does my GMC heater not work on high?

1997 GMC C1500 Heater/AC blower will not work on HIGH. I have replaced the black BOSCH relay behind the glovebox, the blower RESISTOR and the blower MOTOR and still cannot get the blower to work on HIGH. I remember in older model years of GMC’s and Chevys that their was a high speed blower relay that caused this issue.

Why is my blower not working on my GMC Sierra?

When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok. It is a five terminal relay.

Why is my blower motor only working at high speed?

The first thing that needs to be determined is the type of noise that is present and the possible sources. Rattling or knocking noises while… The blower motor only working on high speed is a common symptom of a failing blower motor resistor; but the fact the radio stopped working at the same time is unusual.

Is there a high speed blower motor relay?

Yes there is a high speed relay which sounds like it is out. Here is a guide to help test it and the blower motor wiring diagrams so you can see how the system works with the relay location below as well. Check out the diagrams (Below).

Why does my Silverado fan only work on 3 + 4?

I have an 01 Silverado and the fan only works on 3+4, so a solution would be very helpful if anyone knows one, thanks It’s probably a bad blower motor resistor. I would replace the blower motor as well. Usually what happens is the blower motor gets worn bearings/bushings and pulls too many amps, which in turn burns the resistor out.

1997 GMC C1500 Heater/AC blower will not work on HIGH. I have replaced the black BOSCH relay behind the glovebox, the blower RESISTOR and the blower MOTOR and still cannot get the blower to work on HIGH. I remember in older model years of GMC’s and Chevys that their was a high speed blower relay that caused this issue.

When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok. It is a five terminal relay.

The first thing that needs to be determined is the type of noise that is present and the possible sources. Rattling or knocking noises while… The blower motor only working on high speed is a common symptom of a failing blower motor resistor; but the fact the radio stopped working at the same time is unusual.

Why does my GMC k1500 blower not work?

Here is a possible solution for your 1995 GMC K1500 blower that wont work on high. First remove the glove box and set it aside. Now look into the area that the glove box resided. You will see a wire harness covered in factory foam and next to this on the right you will see a flat silver box that is your ECM.

What kind of blower does not work on high?

1997 GMC C1500 Heater/AC Blower Will Not Work on HIGH. 1997 GMC C1500 Heater/AC blower will not work on HIGH. I have replaced the black BOSCH relay behind the glovebox, the blower RESISTOR and the blower MOTOR and still cannot get the blower to work on HIGH.

Here is a possible solution for your 1995 GMC K1500 blower that wont work on high. First remove the glove box and set it aside. Now look into the area that the glove box resided. You will see a wire harness covered in factory foam and next to this on the right you will see a flat silver box that is your ECM.

Yes there is a high speed relay which sounds like it is out. Here is a guide to help test it and the blower motor wiring diagrams so you can see how the system works with the relay location below as well. Check out the diagrams (Below).

Why is my heater blower motor not working?

Next disconnect the connector and look into the female side of the connector the red wire will show signs of it being loose, meaning that it looks like it has melted, This is due to a loose connection. Now if you opt to get a new GM connector or you can tighten the female connector so that the pin will fit snugly into it once again.

How does the HVAC motor affect the blower motor?

Blower Motor Speed The HVAC module blower motor speed selector varies the blower motor ground circuit resistance by adding or bypassing series resistance in the blower motor resistor. Increased resistance lowers the blower motor speed, and lowered resistance increases blower motor speed.

Why is my blower not working in Hi ( 5 )?

The usual failure of the resistor pack is if it works in HI (5) but not in any other mode or just a few modes. When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok.

What is the fan motor in an AC unit?

What is an AC Fan Motor? The fan motor is a fairly uncomplicated yet vital part of an air conditioner. It’s the part of the unit that pumps air through the system. Without that circulation of air, your AC won’t cool your home.

What happens if the blower motor only works on high speed?

In other designs, the failure of 1 resistor means you lose only one speed. However, most car makers bypass the blower motor resistor completely when you move the fan speed switch to high. If your blower only operates on its highest speed, chances are you have the series type of blower motor resistor. This is the most common failure mode.

When do you Know Your AC fan motor is bad?

If the compressor is working but the fan blades are not spinning, the motor is faulty. That’s your cue to turn the system off and call the pros to repair the AC fan motor. Replacing an HVAC motor is a job that can be done quickly once the problem is identified.