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FIXITMAN, Master Technician
Category: GM
Satisfied Customers: 17343
Experience:  ASE Master Certified
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I just bought an 05 TB and the other day I came out and the

Customer Question

I just bought an 05 TB and the other day I came out and the hvac fan was running.80 deg weather.
I thought it might be to cool the car but that is stupid. Checked on youtube and replaced the resistor pack. No help. If I go somewhere and leave the car, in a couple of yours come our and the fan has started on its own. Could this be if I hit the remote to open the car and it starts the fan to help remove hot air?
Submitted: 1 year ago.
Category: GM
Expert:  FIXITMAN replied 1 year ago.

Hello, my name is Bobby. Thank you for the question. This is a common issue. When you say that you replaced the resistor pack was it the blower control module?

Customer: replied 1 year ago.
It was the Heater Blower Motor Resistor that is in the blower air stream.
Expert:  FIXITMAN replied 1 year ago.

Thank you. It sounds like you replaced the module. The module is usually the issue. The fan should not ever come on if the switch is off and the key is off. If the switch is on and the key is off then it may have a bad ignition switch. If it is coming on when the key is off and the switch it off then there is an electrical short in the wiring. Some of the time it is on the back side of the control module.

Customer: replied 1 year ago.
The fan goes off when I turn off the car but some time later when I come back it is SOMETIMES on. Don't know if it is tied with the remote unlocking or not. I am trying to not unlock remotely to see if that might be the problem.
Expert:  FIXITMAN replied 1 year ago.

Do you have remote start also or just locking?

Customer: replied 1 year ago.
Just locking remote
Expert:  FIXITMAN replied 1 year ago.

Thank you. If the fan is coming on before the key is on then you either have a failing ignition switch or a body control module problem. Unless the vehicle has been modified in some way the blower should only receive voltage with the key on and the system on. Does a lot of air come from the vents when this turns on?

Customer: replied 1 year ago.
I just hear the fan running on the outside through the air intake. Haven't checked to see if air is coming through the vents.
Expert:  FIXITMAN replied 1 year ago.

Does the fan turn off right when you open the vehicle door?

Customer: replied 1 year ago.
I don't think so but I will check next time It does it
Expert:  FIXITMAN replied 1 year ago.

Please let me know as that can give us another clue as to what is causing this. If it stays on suspect the ignition switch. If it goes off then it may be the body control module.