90 climate control prob

First problem noted with blower fan was when it kept running when engine was shutdown. After a few minutes, the blower went off. Hasn't worked since. I tried a new fan relay on the firewall, but no help. I hot-wired the blower to the battery, and the fanmotor ran ok. Any suggestions would be greatly appreciated.

perhaps you missed the correct relay? check it over and make sure.

There may be more than one....the one on the firewall that I tested with a voltmeter, I saw a difference on two of the terminals when I selected different speeds on the climate control panel. The voltmeter readings were only 1.3 volts, but they did switch to different terminals when different speeds were selected.

If you have the automatic air system(temperature control with thermostat settings) it sounds like the blower module has gone bad. They are wired hot and when they fail they short out and the blower will continue to run with the key off. Sounds like yours failed. I've bought them on rockauto.com much cheaper than the dealer. Good Luck!

Thanks for the info.....would you enlighten me as to where that module might be found on the car? Until I figure it all out, I straight wired the blower to the fuse panel through an inline fuse so that the blower runs whenever the key is on. All other features of the climate control work just fine, so at least I have a/c until I can locate all the parts in this system.

Hello,

The blower control module is located on top of the air plenum. You need to take the relay cover off and on top of the air/heater plenum under the hood you'll see an electrical conection about 3-4 inches long that plugs to the blower module. It's the same place as a regular blower resitor assembly would be if your system was manual. Two 7mm. screws hold it down. Pull it straight up and out and replace. Easy as this. The dealer is where most auto parts stores will send you to get this part, but their very high. Try rockauto.com over the internet they carry Delco o.e.m. parts for a fraction of the price. Good Luck! Formzy

Thanks for all that good info! The only thing I could find mounted on the plenum had three screws holding it on and two electrical plugs. When I pulled it out of the plenum, I found it to be held onto a large silver-colored, finned heat-sink with four screws. Does that sound like we are talking about the same part?

That's it!!

Each one is a little different. I was wrong when I said two screws, it does have three or four. If you see the big heat sink you found it.

Good Luck! Let me know if it solves the problem. 99.9% sure.