cooling fan relay location?

2004 BUICK RENDEZVOUS
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MOO DADDY
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the cooling fans are not running when the engine temperature raises up. the fuses don't appear to be blown. how do you troubleshoot the fan operation?
Dec 26, 2008 at 7:18 PM
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KASEKENNY
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Here are some guides that will get you started:

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Once we review this material, I attached the wiring diagram that we need to use to test these relays.

I would start by just jumping 12 volts to the fans and make sure they work. If they do then change out the relays if they don't test okay. Then we need to see where we don't have power on these terminals. Run through this testing and let me know what questions you have. Thanks
Dec 8, 2020 at 12:57 PM
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DANNY L
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Hello, I'm Danny.

I've attached a picture below of the location of the 3 cooling fan relays in the under hood fuse-relay box and circled in red. Here is a tutorial showing what is involved for testing a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

It is also possible you might have a defective coolant temperature sensor that is causing the fans to not come on. I've attached below also a picture of the location of the coolant temperature sensor on your car. Here is a tutorial showing how to replace the coolant temperature sensor:

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

Hope this helps and thanks for using 2CarPros.
Dec 8, 2020 at 1:13 PM
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