Blower motor/air doesn't work 99 granprix


the blower motor switch only works on high for both heat and cooling with engine on. if ignition switch to on but engine not running, the switch works in all five blower settings. all fuses ok and air works on high and compressor engaged. on lower fan speeds compressor not engaged and no blower fan operation. any suggestions?? disconnecting battery to “reset computer” no help. also lights go off in the non functional fan lower speeds and back on in the highest functional fan setting. is this the control module or what?? any easy way to test?


This problem is a little different than the usual one.

Since the lights are having a problem also it appears there may be a grounding problem in the dash area. Also check the grounding wires near the battery to the body chassis. One easy way to check this is to run a test wire from the negative battery post to suspected bad ground areas and tie the other end to a good ground point. If things work okay then, you will know you are on the right track.