97 GMC Jimmy won't blow air - period!

Hi, I have (or rather my wife has) a 97 GMC Jimmy - we bought from a used dealer. They had a shop fix the broken motor mounts. A week or so later the AC stopped blowing cold air. About a week after that, the blower stopped blowing period. Then she was having problems starting the car - we had to jump it a few times. I read that if you take the positive terminal off the battery while the engine is running and the car keeps running (it did) you can be fairly certain it’s not an alternator problem. So we replaced the battery. We had a somewhat irrational hope that this would make the blower fan work - it didn’t.

So today I pulled the blower fan out (An insane process if anyone is wondering. I’m not sure how the heck they got it in there with the wheel well in the way like that). It actually spun using 12vdc from a wall wart (slow, but spun), and spun really well plugged straight into a spare battery. So the blower motor isn’t the problem. Also, I plugged my multimeter into the plug that connects to the fan and read 11-12.3vdc (although my wall wart gave me 17v even though it’s rated at 12).

Are there any ideas about getting my fan to work? Thanks

You should never disconnect the battery cables of a running vehicle. You can do a lot of damage to a modern vehicle’s electronics that way, and it’s not a good test of anything.

If the blower works with 12V applied directly from a good battery the problem is not likely to be the blower motor. It may be in the blower switch or the blower resistor.

If this vehicle has electronic climate control, the problem may be more complex.

Thanks for the response! Well I guess I learned something new - don’t disconnect battery cables!

Well, I managed to break a few laws of physics putting the fan motor back in, and I’m checking out some repair manuals from the library that will hopefully tell me where those parts are.

Typically you cut the blower housing (under the hood) It is even marked where to cut it,did you do that?

For future reference, most corporate chain auto part stores will test battery & charging system for free. If you need a battery, they’ll then install it for you. They sell a lot of batteries that way.

You can apparently use a multimeter and coupled with the repair manuals you should be able to figure it out. Post back when you do.