No power to blower motor

[89Cad]

I have an 89 Deville that is getting no power to the blower. I had a friend mechanic of mine look at it and he said fuses and relays are fine but he cant figure it out. He advised me to take it to a dealer. I'm sorry, I just dont trust them and the price they will charge, not to mention the hassle of just getting it in with no back up vehicle. Does anyone have an idea? Would really appreciate any suggestions. Thanks

[MarkC]

I take it the blower motor won't operate at any speed, so try this test. Disconnect the two pin connector at the blower motor. Connect a voltmeter across the two pins on the harness side of the connector. With the engine running, select the High blower speed and check the voltmeter. If the voltage is greater than 4 volts, the blower motor is faulty.
Sometimes the Power Module goes, but when that happens the blower motor will still work, but only on high. Its happened to me before with my 89.
Let me know how you make out.

[GritMaster]

Same thing work in a 79? :P I have (I think) the same problem, the blower was just replaced a year ago and my mechanic said to replace the ac controler, which i did to no avail, all the fuses are fine and I cant find any problems in the wiring....

[MarkC]

No idea about your 79 :-( You would need to purchase a service manual for it in order to do a complete circuit check. Ebay has them for sale occasionally.

[GritMaster]

I own a service manual already, just the thing is way to friggin long :P
theres like 60 pages on the AC alone....

[hyarnell1]

There is blower control module in the engine compartment on top of the A/C plenum, about 8" towards the passengers side from the blower motor. These are notorious for going bad; usually they short full on, and the blower never shuts off.
Check salvage yards,as these were used throughout the GM line in this time period.

[89Cad]

Originally Posted by hyarnell1

There is blower control module in the engine compartment on top of the A/C plenum, about 8" towards the passengers side from the blower motor. These are notorious for going bad; usually they short full on, and the blower never shuts off.
Check salvage yards,as these were used throughout the GM line in this time period.

Harry, you were on the money. Nobody, including my mechanic mentioned this as the potential problem. And I discussed it with a lot of people. For your information, my fan was not stuck on high speed as I later learned is a good clue that the module is bad. My fan didnt work at all. Thank you very much for the info, it saved me a bunch of money and aggrevation. By the way the part was $9.00 at a salvage yard. Thanks again to you and all else who replied. This forum is very helpful.