AC blower motor issues

My daughter loves her new Grand Prix a gently used 2005 that is really her first car. She’s even named it. But she has had major headaches with the dealer she bought it from, getting them to fix various little things. We’re loathe to go back with this newest!!

Her AC fan suddenly started acting up, would take a long time to come on and then had only two settings: OFF and FULL BLAST. After a couple weeks, it stopped working all together, only a couple off times now, it suddenly decided to come on (FULL BLAST)and would not shut off, even after the ignition was off and the key removed!! A car mechanic friend accessed the blower motor, and disconnected it - but before we yank it out and possibly replace it - does anyone have any details on this problem. Have found several mentions online of the problem - but no “fixes” that sound rational (One - said the windshield wipers intermittant charge had fried the module that is shared w the blower??? and it needed to be replaced and buffered somehow?? (“a TCP hard wire in front of the module”)

Any comments out there? This sounds like a design flaw to me. Should it be covered under the extended warrenty she has. We’d like to avoid the dealer if its a simple fix.

From how you describe the problem, the HVAC module/blower control processor would be suspect. This is what supplies power to and what controls all the blower motor speeds. The blower control processor has voltage supplied to it at all times. But the HVAC module controls the grounding of the processor to provide the various blower speeds.


Thanks. Am contemplating switching this part out to see if its a fix. Is it located next to the blower motor itself (which is in the front passanger footwell) I’m finding multiple items with similar names at online parts suppliers at a wild range of prices - so am trying to pinpoint this thing.

I assume the speed control for the blower motor is the variable speed type and not the type that uses fixed speed positions. The variable speed control type systems use a solid state speed controller that is controlled by the HVAC system like Tester mentioned. I think the trouble is with the solid state controller module and not the ‘brain’ of the system. The modules can either short out (not to ground, the input and output) which cause the blower to run full blast or they can open which will leave you with no blower. No power gets to the motor. The module you are looking for will be connected to the wire running to the motor. The module will be mounted on the air ducting for cooling. The modules cost around $100 dollars for the part.