I noticed this problem when I attempted to start my car and my battery was dead. I jumped my car off and the air was blowing while the car was off. I had to take out the hvac blow motor fuse #25 to stop the problem temporarily. My car still blows air using the **** but it will not blow hot air only cool. What could possibly be the problem? Wire touching?

 

What year is your monte carlo? I had an issue with my 02 impala ls when I still owned it, put the heat on 5 and when I turned the car off it kept running, it took it 5 minutes for it to shut off. 00-03 had different blower controls from the 04-05's. I know the older controls had issues with the blower motor resistors, that could be your issue I'm not sure. Ours also wouldn't work on number 1, now I have my 04 monte carlo with the different blower controls and haven't had an issue with those. I'd think its either your blower motor resistor or the ignition not stopping power when the car shuts off. Don't know how to go about troubleshooting though. As for the no hot air scenario, the temp actuators in the dash can go out, and get stuck in the temperature they were at while working. You can smack them with a screwdriver not to hard and see if they work again, if not you'll probably be looking at replacing those. I read about the screwdriver trick, and used it when the recirculation door for my a/c wouldn't work.

 

Sounds like a faulty ignition switch to me...

 

I just went through this issue this spring. The issue is probably the blower motor resistor. It is a pain to replace, but fairly cheap.

For now, unplug the power from the blower motor. the resistor is inline with the power, and when it fails it will run until the battery is dead. removing AC/blower fuses will not stop the motor from running if the resistor has gone bad.