HVAC Blower 99GT

A few days ago the blower speeds 1-4 stoped working (fan did not come on), but HI worked. Checked HVAC control fuse(s), all were OK. The next day, HI blower came on, but the blower did not stop when the fan switch was turned to off, nor when the ignition was tured off - had to remove the HI blower fuse to get it to stop.

Any ideas? I saw a post elsewhere in this forum about a bad "blower resistor module" causing some fan speeds to not work; does anyone agree that this could be the cause? Would this module's failure cause the blower to run on HI with the ignition off?

Where is this module located?

Thanks for your help!

Hello, i've been having alot of problems with my blower motor too. Like, if i turn it off when i park it for the night, and come out in the morning and the engine is cold, when i turn the blower on any speed, regardless of where it's supposed to come out, all i hear is a loud whir-whir-whiring and whining. I have to turn the motor off and on several times to get it to stop. But If i leave it on over night, when i start my car up the next moorning, it works just fine. And i figure i'd ask around before i tore it all apart. Anyone got any suggestions?

I had the exact same thing happen to me recently, did you ever discover where the blower resistor is located?

Your assistance is greatly appreciated.


A few days ago the blower speeds 1-4 stoped working (fan did not come on), but HI worked. Checked HVAC control fuse(s), all were OK. The next day, HI blower came on, but the blower did not stop when the fan switch was turned to off, nor when the ignition was tured off - had to remove the HI blower fuse to get it to stop.

Any ideas? I saw a post elsewhere in this forum about a bad "blower resistor module" causing some fan speeds to not work; does anyone agree that this could be the cause? Would this module's failure cause the blower to run on HI with the ignition off?

Where is this module located?

Thanks for your help!

OK Guys here is the scoop. The blower will work on various speeds because of the fan resistor. It acts like a rheostat to allow the fan to work at different speeds. When the resistor begins to malfunction it will only allow the fan to run at certain speeds usually it will start with one speed not working and then gradually only the highest speed will work. The resistor is located under the dash next to the fan. It is a real bear to get to and could take as long as an hour to replace. You usually end up removing the fan to get enough room to replace the resistor. The only place you can buy one of these is to go to the GM dealer. They cost about $20.
As far as the fan running with the key off there would have to be a short somewhere in the system to cause this but it could also be caused if the resistor had partially shorted out. I would replace the resistor before preceeding any further as this may solve all your problems.

I could not have said it better. Check the resistor, it might have shorted out and that is why was on all night. Do that before going deeper