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Cooling Fans not working correctly - trying to locate relay switch

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1 hour ago, Susan48 said:

My car is overheating then the second cooling fan will kick on. Parts store told me it was my relay switch. But I can't locate it. Can some one please help me?

Greatly appreciated! 

How did they determine it was a relay?

Please post your year and model.  You have an onboard diagnostic system that if something is wrong it will set a code.   There are 3 relays for the cooling fans.  Do you know how to check the codes?


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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  • 3 months later...

The cooling fan relays are attached to the lower radiator support, behind the radiator, between the two cooling fans. There is a 10mm bolt under the car on the rad support that holds the relay pack to the rad support frame, remove this, then slide the pack towards the passenger side which will release the catch 'foot'. There is a small clip holding the one of lead wires for the relays hanging up about 3" away from the pack, release this, then push the back of the pack (wiring side) up towards the hood, pull the relay pack down by grabbing the plastic relay covers and GENTLY work the mounting feet past the ac lines. The relays will be hanging down at this point. There are 3 relays on the mount. Staring at the pack from the front of the car the relays are as follows.

Left relay: Low speed fan control.

Center relay: Left fan hi-speed control.

Right relay: Right fan hi-speed control.

I had the center relay fail, this left me with low speed fans, but only one hi-speed fan.

The relays are fairly expensive, but the headlights use the same relay, so I grabbed 4 on a junkyard run and just replaced all 3, as they get cooked to death behind the radiator. When my relay got hot, it couldn't close the circuit to turn the fan to high speed.

My question for you would be the same as above though...

How did the auto store employee find out that it was the relay? Did a code come up?


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