Hi,

I posted a few weeks ago about the HVAC circuit that would not turn off with the key in the off position, it continued to run. I replaced the blower control module and it did not fix the problem. Someone told me that GM switches the ground circuit to control the HVAC. Is this a possibility, could I have a shorted ground wire? Also, I am having some strange things happening with the “Driver Information Center” and the Traction Control switch not working. Any ideas where to look for some shorted ground wires, or any common place where I could have some wires rubbing?

Thanks for the help
Mike
97 SSE with electronic climate control

The control of the blower motor is from the purple wire, which is the positive lead. A shorted ground would have no effect on the blower.

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Blower Control Module

DESCRIPTION

The Blower Control Module is a solid state device that operates the blower motor. The Blower Control Module outputs a voltage that varies between 0 volts (blower motor OFF) and 12 volts (maximum blower motor speed).

OPERATION

To determine the appropriate output voltage, the Blower Control Module monitors a varying voltage signal (between about 2 and 8 volts) from the Heating Ventilation and Air Conditioning (HVAC) programmer. The module then amplifies the signal and applies voltage directly to the blower motor. Blower Control Module output voltage is also monitored by the HVAC programmer
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The gray wire (according to my 93 diagram) is the "varying voltage signal (between about 2 and 8 volts) from the Heating Ventilation and Air Conditioning (HVAC) programmer". Test this wire for voltage with the car off. If there is voltage present, I would have to say that there is a problem with the programmer. If not, it'* another bad BCM.

Was the BCM replaced with a new or used unit? I have an extra BCM. It dosent work on HI but works nevertheless. I can send it to you if you would like it for trouble shooting.

randman1

Your sig .... now thats funny.... yep yep yep yep




JLathem

The BCM was brand new. Thanks randman1 for the offer on the used BCM. Let me do a little more research. Is there anyway to get a wiring diagram of the HVAC power circuit?

Thanks
Mike

what is your email? i can send one to you.

Thanks John Deere Boy!

mvh_2000@yahoo.com

Mike