03 Envoy dead battery

[bobec]

Hello all...

I have an 03 envoy slt. 70k. My problem is after the key is taken out of ignition, the blower motor continues to run. (Draining the battery). I've taken out the 40 amp fuse that feeds the fan as a quick fix. But was wondering what the real problem is. I've tried turning off the fan while car is running, but fan comes on at a low speed after engine is shut off. Thanks for any advice.

[envoyxuv]

Do you have automatic heating and air conditioning controls? Automatic controls have the blue light up digital display.

[bobec]

Yes. all options on car except side curtain air bags.

[envoyxuv]

Okay, thanks for the info. i have run across this issue before. GM has a service bulletin, #06-01-39-002A regarding this concern. It states that the condition only occurs in low ambient air temperature conditions, which i don't believe, because i've seen it happen in the summer.

Anyway, there's an issue with the blower motor control processor (also called a linear power module- just don't call it a resistor, or you'll get the wrong part from a parts house/dealer). The module will internally short the motor to power = motor stays running all the time. This processor takes the place of a blower resistor and is only used on the automatic controls like you have.

The processor is located down by the blower motor under the dash on the passenger side. It connects to the case with two 7/32" bolts (very small bolts). It has two wires coming from it that plug into the motor, and a 3-wire connector plugged into it with a red wire, black wire, and a purple wire with a white stripe on it. It is a standalone part and does not require programming when it is replaced.

[bobec]

Thanks,

fyi... I tried to get the part at two different auto part stores, with no luck. They both told me it is a "dealer item". I went to my gmc dealer, they had to order the part (139.00+tax, ouch!) and i'll put it in tomorrow. Thanks again and I'll let you know how I make out.

[envoyxuv]

Cool! i'd definitely like to know how that turns out.

[bobec]

That was it.... Once the dealer got me the correct part, two bolts and ten min. I was done. Thanks again, you saved me at least two hundred bucks!!