My heat/AC fan motor will not shut off even when the car is off and keys are out...

Bad switch. The switch allows power to continue to run to the other side of the switch. The slow or med. speeds also run off the switch and replacing it may fix it all.

Thank you Mark for getting me started. I took out & unplugged the fan control switch, the blower motor would still run. I checked under the dash on the passenger side to find the blower motor and found a blower motor resistor. I replaced that and everything worked. Found out it is a common problem. This resistor causes anything like the motor not turning off, the motor runs only on one speed, or not work at all. I found the part at my locale parts store. $60.00 bucks worth...

Glad you were able to locate and isolate the problem. Just a note, on the bottom of the page is the words, "Mark helpful". It is a command that if you feel the suggestion is helpful to click on it. My name is not Mark helpful, but John Carson. Unless Mark did respond and point you in the right direction. Enjoy your air conditioner. :-)

Thank you John C. I am new to this web sight and appreciate being pointed in the right direction...

The reason I know about the "Mark" thing is because I did it also so don't feel alone. Stay on this site and you'll get a chuckle from others that thank Mark. Welcome.

How did you do that and what part did you need. I am clueless when it comes to cars. Mine started doing the exact same thing last night. My car even went dead and it was still running, my dad unhooked the battery for it to stop. Also, I did replace an acuator under the glove box due to it clicking about a 6 months ago. My dash acuator also clicks, haven't been able to locate it. And, it's not me doing this, it's my dad. Id rather not have to pay 500 dollars at the shop. Any info would be greatly appreciated and if you could dumb it down the best you can that would be great as well!! Lol

What it is, is the blower motor resistor. It is located down by the blower motor. Just follow the wires from the blower motor plugin to the resistor. I replaced mine 5 times with aftermarket resistors until one finally stayed working. You might opt to pay for an OEM part instead of an after market part.

I have the same problem and have replaced the resistor twice with an AC Delco genuine part, but still doesn’t solve the problem. Was told the ignition switch was causing this since the dash lights would come on as well as the blower. Mechanic replaced ignition switch and it fixed the dash lights from coming on, but not the blower. This happens all without the key in ignition. Please help anyone!

Could also be the blower relay, or also the blower conrtol module which is close to the blower behind glove box. Had a similar problem today, hope you figured it out by now.

I have an 2005 impala and I replaced the blower, switch, and still can get the fan to turn on. I direct wired the fan to the battery just to make sure it worked and yes it does. The switch is also working cause when I shut the a/c off I hear the compressor turn off and on. I just can’t get the fan to turn on.

I have a 2005 Chevy Impala I turned my heat on in the car cause I was cold and I turned it back off and it didn’t cut off it was still blowing and my air conditioner will not turn off even with my keys out of the ignition unless I unhook my battery help me please