You are here:

Cadillac Repair/AC Blower Motor Relay

Advertisement

Expert: - 7/15/2009


Question
I want to know where the airconditioning blower motor relay is located.

Answer
Hello,

You did not specify year or model, but that's ok.

Here is the bad news--these vehicles don't have the standard hi and low blower relays.

Cadillac has had issues with the blowers since the early 80's. Did they ever fix a known problem? Never did!

These cars were notorious for one of two blower problems-either blower would not shut off and battery went dead, or blower did not work.

The wonderful Cadillac engineers designed a relay module with a circuit board to control speeds. Module was notorious for failing electronically located on passenger side of cowl area under hood.

The only way to repair was to hard wire with resistors around this module to control blower speed and be able to control on or off. The other option was to pay $400-$500 to have the module replaced just to have it fail in the future.

I am a Cadillac man, however they do have many of the same problems over the years. You had a 50/50 chance of getting a good engine when purchased new. I have dealt with the factory knocks in the 4.1, the 4.5, the 4.9 and the Northstar. I even was involved in the 81' 4-6-8 368 CI engine which was great when the computer was disconnected where it ran on 8 cyl all the time.

The North star when introduced was raved about, but after it had been around a while, it was notorious for burning oil and dare not over heat or the aluminum block or head gaskets were shot.

I realize I wandered away from your question about the relay, but I am just saying these vehicles had inherent problems. The blower being one and the engines the other.

Where these relay modules for the blower motor were mounted were above the heater core. the easiest way to find is follow the blower power wire up.

Rob

Cadillac Repair

All Answers

Answers by Expert:

Ask Experts

Volunteer

Rob Painter

Expertise

Alarm system questions cannot be answered on this forum. These systems are not what I can answer. Without being physically at the vehicle and not knowing what kind of electrical service has been done on the vehicle, there is no possible way to give an accurate answer over the internet. My expertise is in Ignition/key based anti-theft systems. These issues include GM VATS (resistor chip in key blade) PASSLOCK (MRD)-ignition lock rotation based, no special ignition key and the PKIII Transponder (computer chip in key) systems. These systems are not alarm based and are integral with the starting of the engine. This is why I cannot diagnose alarm problems without physically looking at the vehicle: Alarm systems are a completely different annimal than ignition key/lock based anti-theft system. Many alarm questions come from vehicles 10 years old, and since older, many hands that had been involved over the years.I am an expert in all GM factory (ignition/key based)systems. Alarm system questions pose to many situations beyond my knowledge as to what has been done to the vehicle over the years. Some guy may have actually wired the stereo into the alarm system. Who knows? Over my past 30 years in vehicle wiring repair, I have seen unbelievable wiring disaters done by guys that consider themselves "mechanics." I have seen stereos and alarms intalled using surgical tape. I have seen modules burn up, un-fused circuits, wiring jambed between the doors and even lamp cord used for a starter kill. To answer alarm questions over the internet without examining the vehicle is like asking; What does it take to remove a dent?

Experience

Education/Credentials-ASE certified. 11 years with a GM dealer and 17 years with a repair facility dealing with only the repair of theft recovered vehicles.

©2012 About.com, a part of The New York Times Company. All rights reserved.