climate control question

[gar]

So the vents/footwell/defroster won't blow on my suburban.

Any suggestions for troubleshooting, or do I just need to buy a new blower motor? The rear a/c blower works fine, thankfully.

-Garrett

 

[pauly383]

Well after checking the fuses first , you can run 12 volts right to the motor and see if it blows , or if you have a friend with a Chevy/GMC , ground your motor to his truck and put his plug on it . I never had a switch go bad yet ( knock on wood ) so I can't say after you checked the motor and fuses

 

[cbbr]

Make sure that you have a good ground also.

 

[dyeager535]

Does the fan motor work? Turn the key to "run", and turn the fan on its various settings. You can hear it run if it's working.

If it runs, and you have AC, I'd suspect the blend "switch" in the control unit which is vacuum controlled.

If the motor doesn't run, determine if the blower motor is getting power and work backwards from there.

 

[gar]

well, with the truck turned on, the fan doesn't run in any setting. If you turn the heat on, you can feel heat eminating into the passenger compartment as a result of air being forced through the system while driving. The A/C does work, as the rear a/c will blow hard and cold.

Thanks for the help so far, and I'll probably be posting with more questions as I try to troubleshoot this.

-Garrett

 

[dyeager535]

I believe fan issues have been covered a fair amount recently if you can search, if not, someone will probably have more info than I will.

AC uses a relay as well as a resistor IIRC, while my non-AC setup is pretty much a brown wire from the fuse panel to the switch on the dash, then wires from the switch for each fan "speed", with a resistor setup on the heater box, and a single wire from that to the motor, with a motor ground.

AC probably isn't much different, the fan motor is still controlled electrically, just the vents (most I believe) are handled by vacuum.

First thing first, I'd check the wire going to the fan motor for voltage when the fan SHOULD be runnning.