Heater blower not working
Thread Starter
Heel & Toe
Joined: Jun 2010
Posts: 22
Likes: 0
From: Hilton New York
Heater blower not working
I have a 1991 couple. The blower motor doesn't come on. I removed the blower and bench test it, it fine. Replace the control module with a used one (beleive its good) still no power to the motor. Could it be the blower relay? Thanks Tim
Racer
Joined: Oct 2011
Posts: 312
Likes: 0
From: state of insanity
:Hate to ask ,but did ya check the fuse? If ok check to see if you have power to the relay,if you have power to the relay and in op fan,i would think the relays bad. Also check the fan speed control i believe its mounted to the top of the evap.housing IF WORSE COMES TO WORSE GET YOUR SERVICE MANUAL AND FOLLOW THE TROUBLE SHOOTING GUIDE 
Last edited by mtnmanut; Nov 14, 2011 at 12:02 PM.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
There's no Relay that I know of (Electronic Controls) with the Module simply taking low voltage inputs from the Programmer and ramping them up to run the Blower. Start by checking for 12 volts on the red wire at the Module (mounted on the left side of the Evaporator Case). If you have a Shop Manual it will give the Schematic for Blower Controls in Section 8A and whatever nomenclature GM uses for the fuse that powers up the Module. For example, there's a 5 amp fuse GM labels PGMR and that's protecting the Circuit which returns actual Blower voltage (the ramped up number) to the Programmer. I'm pretty sure that isn't open because when it is open, the Blower runs at full tilt even with the ignition off. Earlier years power up the Module through the a/c fuse, but I'm not sure about the '91, so use the Schematic to see just what it is called. Then if there's no voltage on the red wire, open the box and see if the fuse is open.
Burning Brakes
Joined: Jan 2017
Posts: 961
Likes: 237
From: Diamondhead Mississippi
St. Jude Donor '17-'18-'19-'20-'21-'22
Do you have Electronic Control, C68, or standard, C60. Either way if blower works on AC it should still work on heat unless something is wrong with control.
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