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89 DeVille AC Blower Keeps Running

10-01-2005, 05:36 PM
My 1989 Cadillac Sedan DeVille's Climate Control had been working fine until this afternoon . . . The blower motor now runs on high speed all of the time no matter what the setting . . . even when the Climate Control is turned to the "off" position. Even worse, the blower motor stays running on High Speed even with the Ignition turned "off"... I disconnected the wire on the blower motor so as not to fully discharge the battery. It seems as though there must be a High Speed Blower Relay "stuck on."
Any suggestions ? Or is it "to the Dealer I go ???"

10-01-2005, 06:23 PM
welcome to AF.
well you are right in a sense; back to the dealer.
that is because no one in the aftermarket is probably going to have the fan resistor.
it may be a relay; you could find out easily.
hook the blower back up, open the relay box, and start pulling A/C, fan, blower, climate control, etc. relays until it goes off;
then "borrow" one of the same type from another source (since the vehicle isn't running, just power on, a fuel pump relay or ignition relay is probably the exact one) and plug it in, and see if it stays off.
if so, I'm wrong, and a relay CAN be found at most parts stores for around $10. US Dollars. if it jumps back on, you are going to have to head to the dealer for a resistor unit.
'89 is border year... you may still be lucky enough to actually have the old type (an actual resistor) which will be under $35. (maybe less, as if resistor, probably fits many other GMs), but you may have what Cadillac and Olds refers to as a A/C Blower Control "Module" which is naturally over-priced somewhere in the $80-120. Dollar range.

BUT--- before you go this route, you may elect to get the A/C diagnosed, as it could be the actual Head unit (your digital display box on the dash itself) and this you don't EVEN want to talk to the dealer about.

if you end up needing either part, and don't want to be "dealt" to the dealer;
Arapahoe Auto
(cadillac only)
Donnie Hunter is owner/operator
Englewood, CO
800-229-0875 or

he will FedEx anywhere. Family owned for three generations, and if he doesn't have it, can't get it, you are stuck with dealer or a toggle switch mounted under the dash as a kill switch.

good luck,
hope this helps,
nrt racing

10-28-2005, 09:16 PM
Thanks very much for your ACCURATE information!
A trip to my local Cadillac dealer and $ 200.00 later my Electronic Climate Control performs flawlessly... it was the power module ($ 126.00). I agreed to the Service Advisor's suggestion to have the AC diagnosis performed, also... everything else was "ok". At $ 96.00 per hour labor, it doesn't take long to spend the dough ! A recent purchase of a pre-owned Factory Service Manual on eBay for $ 16.00 hopefully will help me with a little diagnosis with any future problems. I must admit, however, that I am much better with understanding an old-fashioned wiring schematic than I am with the newer "flow-charts" that are now used.

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