Where is the Cooling fan motor relay???

Hello,

I have found the locations for you and a test guide so you can confirm the failure.

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

If the cooling fan is bad this guide will give you an idea of what you are in for when doing the job.

https://www.2carpros.com/articles/replace-electric-fan-motor

I have also found these diagrams to help you see what you will be fixing.

Please let us know what happens.

Cheers

I uploaded a picture of the compartment I think you are referring to with the top diagram showing. Can you tell me which relay it is? No water in the cooling system? Is that the radiator overflow?

P.S. I wired the fans directly to the battery and they worked fine so the motors are good Thanks

The legend on the post above shows which relays are which. Check it out :)

Yes, I uploaded a new photo

Is that relay box behindthe drivers headlight. My software says the round relays and 1 square are for the fan, there are 3

Well this power box sits behind the battery which is behind the drivers headlight.

I will remove the battery so that I can get directly behind the headlight and see whats there. I will take more pictures if I need to. I really appreciate the time you have spent to try and help me. I will keep you posted

unbolt it and turn it over so you can find the wires with the same color as the ones that go to the fan

I am sorry for the late update and feedback. I found the relays. The power box was actually located under the drivers headlight and casing. I had to remove all the drivers side lighting units and then the casing. Anyway I replaced all three relays and the fans are still not coming on, even when I turn on the air conditioning. The car is still running hot! Do you have any suggestions.

By the way, you have been very helpful so far. I will definately leave great feedback

Okay it seems like you may have a blown head gasket which I have seen cause this problem. Here is a couple guides to help us see whats going on.

https://www.2carpros.com/articles/head-gasket-blown-test

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please let us know what happens.

Cheers, Ken

Engine Cooling problem
1990 Lexus LS 400 V8 149,00 miles
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I have recently started having problems with over heating , I haven't noticed any leaks and replaced thermostat after testing it first. After doing so I noticed that my cooling fans wont come on during idle but wille come on during driving. Is this problem simply a relay or could I have more serious problems like a blown head gasket? And what is the best way to determine head problems?

Check the relays and the fuses, also the water temp switch in the side of the radiator, as for the head, you see any white smoke from the exhuast?

White smoke would indicate a possible head gasket or warped head problem. They are now making products to use in the radiator to seal head gaskets, I don't know how effective they are.

The cooling fans only turn on with the ac being on. I have replaced the temp switch that is in the radiator, and the temp sensor on the intake, along with 3 fan relays. I still cannot get the fans to turn on.

Check for power on the Yellow/Blue wire at the Water Temperature Switch (located on the left front of engine compartment - on the radiator).

Next make sure that the White/Black wire on the Water Temperature Switch makes a good ground. (Use an ohmmeter. With the Water temperature switch disconnected, connect one ohmmeter lead to the wht/blk wire on the Water Temperature Switch connector and the black ohmmeter lead to the negative battery terminal. The ohmmeter should read "0". If not. Clear the area where the Water temperature switch grounds on the right front fender.)

I checked the ground, it reads 0. I used a probe to test for power pin the yellow wire. No power.

I went back and tested for power with the ignition in the on position. There was power.. Where do I go from here?

Check the IGN fuse (7.5A)

Cooling fans wont turn on, But Fans work and Relays or go.

Since you have power with the Ignition ON, Ignore my request for you to check IGN fuse (7.5A).

Connect a voltmeter to the ground side of the temperature switch (the WHT/BLK wire) and let the engine run until it reaches the temperature where the fan would normally come on. If the voltmeter reads Battery voltage, then the temp switch is working properly. You'll have to check the cooling fan relays. Easiest way to do this is to switch them with an identical relay (the fuse box usually has more than one identical relay). After the switch, it the fans work, you know that the original relay was faulty.

LOOKS LIKE THERE ARE DIFFERENT ONES THAT FIT YOUR RIG (LOOK AT THE CONNECTOR)

SEE THIS LINK

http://shop.advanceautoparts.com/web/PartSearchCmd?storeId=10151&catalogId=10051&pageId=partTypeList&suggestion=&actionSrc=Form&langId=-1&searchTerm=coolant+temperature+switch&vehicleIdSearch=21304&searchedFrom=header

IN THAT "LINE UP", THE "SWITCH" (PLASTIC CONNECTOR) TURNS ON THE FANS, THE OTHER ONE, THE "SENSOR" (WITH THE SPADE CONNECTOR) IS FOR THE IDIOT LIGHT OR GAUGE. (I DON'T KNOW WHY BOTH CAME UP ON MY SEARCH)

ON THE SWITCH, IF YOU GETTER ALL WARMED UP AND RUNNING, THEN REMOVE THE CONNECTOR FROM THE SWITCH BODY, SHORT THE PINS ON THE CONNECTOR WITH A PAPERCLIP/ ETC. (DON'T BEND THE PINS!) YOU SHOULD BE BYPASSING THE SWITCH (AS IF IT WAS "MADE") AND THE FANS SHOULD COME ON COME ON. THIS MIGHT VERIFY WHETHER THE SWITCH IS BAD OR NOT, BEFORE YOU BUY ONE.

IT COULD BE THAT MAYBE YOU KNOCKED THE CONNECTOR OFF, OR THE UNIT JUST WENT ON THE FRITZ.

I RECKON YOU ALREADY LOOKED THE FUSES OVER TOO?

JUST A COUPLE OF IDEAS!

THE MEDIC

The temp sensor and fan relays are new.

Check COOLING FAN RELAY 2 to see if it has power on terminal #2 (remove the relay and check for power at relay socket #2) with the ignition key ON.

Also, with the IGN switch ON, check (for power) relay sockets #1 for COOLING FAN RELAY 1 and 2.

Next, with the IGN switch ON, check for power at relay sockets #3 & #4 of COOLING FAN RELAY 3.

If this doesn't turn up anything we'll check the ground and control sides of the relays.

Does both fans run when the A/C is turned ON?

I will check these out and let you know. Yes both fans turn on with the AC.

The relays have power as you stated, however i tested them twice and the second time they did not.. Im thinking that the connections are bad...? Would i replace the whole relay box? or is there a way to fix the connections?

I read about a guy that his fans won't go on when it gets hot I have the same thing after a dealership put in a new water pump did you Ever figure out what it was that the fans did not go on ?..

If the fans were working before the dealership worked on it, but not after, take it back to the dealership.

If you want to troubleshoot it, we can help you with that. Can you check voltage and ground at the fan connector? Check applicable fuses. Check for applicable trouble codes.

Try the tests again, except this time after you've completed the first test, turn the ignition switch off for a few seconds and then back on and run the test a second time. See if this time it looses power.


By the way the sockets can be squeezed, ever-so slightly to close them up a bit (but this may require you to remove the fuse box [no my first option]).
Or, with extreme care you could bend the "blades" of the relay outward the smallest amount to make them produce more contact (a better option because if you make a mistake the relay is easier to replace than it is to fix the fuse box) [only try this on one relay and if successful try another].

**** CAUTION **** You have to be careful with either option when bending the blades or squeezing the socket or you could ruin the relay or connections in the fuse box.

Check the 30 amp fusible link.

Also, check the 7.5 ignition fuse.