Radiator fan relays

1999 CADILLAC DEVILLE
187,878 MILES • V8 • FWD • AUTOMATIC
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JWGROFF05
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I have located the cooling fan relays in my car below the fan. I am wondering which one would be the main relay for them turning on since mine do not activate. I believe there is one for high speeds and one for low speeds. Which of the three controls the fans going on and off? Is it the middle one the one on the left or the one on the right when looking under the hood. Also, my car leaks antifreeze fast and I do not have a head gasket problem, I do not have a blocked radiator and I do not have a malfunctioning thermostat. There is no leak present anywhere under the car. Would the leak come from the excess flow hose on the reservoir and with failing fans would this force it out?

Is there an easy way to get to these three relays? I was looking and saw I would have to remove the fans, the radiator the main hose from engine to reservoir to even get a hand down in there since they are on the top side of the bottom under part of the bumper. Also, looking at the diagram which one would regulate complete power to the fans in general?
Mar 21, 2011 at 2:19 AM
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FACTORYJACK
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The three relays can be accessed from under the front of the vehicle near the radiator, there is a 10mm bolt that secures the bracket, it can be slid over and brought down for some access.

Here is a guide to help you test the relays

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

Before you go chasing relays, which are fairly uncommon, does the fans come on when A/C is requested? If they do, then they are probably functional. You specify that it uses coolant at an accelerated rate but there is no external leak, that would suggest to me an internal leak. You also specify that it has no head gasket problem, how was this determined? The reason I ask, is that head gasket leaks are probably the most common cause of mysterious coolant consumption and/or overheat, aside from external leak or low coolant. To answer your question, the three relays give both the fans two speeds, low and high. I have included your a schematic, for reference below.

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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Mar 23, 2011 at 2:30 AM
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STRAILER
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Below is a fan wiring diagram. Please let us know what happens.
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Mar 2, 2017 at 11:07 AM
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DCRAB16
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Where is the cooling fan relay on a 1999 cadillac deville?
May 9, 2019 at 5:30 PM (Merged)
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WRENCHTECH
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It has 3 of them and they are attached to the bottom of the fan assembly, between the two fans
May 9, 2019 at 5:30 PM (Merged)
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JRPERKINS76
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were is the cooling fan relay
Dec 31, 2020 at 10:57 AM (Merged)
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FACTORYJACK
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There are three cooling fan relays that give two fan motors low and hi speeds. The relays are at the lower center of the radiator core support, look down approximately at the center, between the two fans.
Dec 31, 2020 at 10:57 AM (Merged)
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TONYF.
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where is the cooling fan relay located and how do i diagnose if it is working? thanks for the help
Dec 31, 2020 at 10:57 AM (Merged)
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STRAILER
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Yes, first check the fluid level, when they installed the transmission did they flush the cooler? if not metal from the old transmission is now in the replacement trans and causing problems. Here is the coolant fan relay location in the diagrams below.

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

Check out the diagrams (Below). Please let us know what happens.
Image (Click to enlarge)
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Dec 31, 2020 at 10:57 AM (Merged)
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TONYF.
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I don't believe the cooling fans are coming on. in stop and go trafic it heats up. highway driving it stays around 195 degrees. where is cooling fan sensor located and what is the proccess to diagnose it.
thanks
Dec 31, 2020 at 10:57 AM (Merged)
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BMRFIXIT
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DID YOU CHECK THE FUSES AND RELAYS if sensor is bad you will get a check engine light saying so any how you should check the fuses and relay sensor is in the water jacket the the rear of the engine good luck


https://www.2carpros.com/forum/automotive_pictures/99387_Image_6.jpg


https://www.2carpros.com/forum/automotive_pictures/99387_Image1_2.jpg

Dec 31, 2020 at 10:57 AM (Merged)
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DUSTYFLH
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Where are they located?What temps do kick on?I read they dont kick on till 220 degrees,what is up with that?
Dec 31, 2020 at 10:57 AM (Merged)
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BLUELIGHTNIN6
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your vehicle has 3 cooling fan relays, all located rearward of radiator , center bottom between cooling fans. the PCM tells the fans when to turn on, not the relays. The low speed fans do not come on until the temp. exceeds 223F and high speed will not come on until temp. exceeds 230F.
Dec 31, 2020 at 10:57 AM (Merged)
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CATHY411
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1995 Cadillac Deville
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where is the radiator fan relay located
Dec 31, 2020 at 10:57 AM (Merged)
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MERLIN2021
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There are 3 of them, they are behind the washer fluid reservoir on the left side of the engine compartment.
Dec 31, 2020 at 10:57 AM (Merged)
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BUZZSAW
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[quote:03a527508e="merlin2021"]There are 3 of them, they are behind the washer fluid reservoir on the left side of the engine compartment.[/quote:03a527508e]

they are under the car, remove the plastic drip pan under the car and there right below the radiator
Dec 31, 2020 at 10:57 AM (Merged)