Cooling fans will not turn on

Good afternoon,

The coolant sensor that controls the fans is on top of the motor at the distributor. I attached a picture for you to view. Check that sensor.

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

I am worried from the overheating that you may have damaged the head gasket.

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

Roy

ASEMASTER6371 the one near the distributor are the ones I changed. I have no water in oil no bubbles in radiator do I need to continue with the compression test and so forth? And would changing switch on radiator help?

You could try changing the switch, yes.

Yes, I would still do the test for the head gasket.

Did you check for voltage at the sensor and the switch at the radiator?

Roy

No sir, only the sensor but will check the switch. Any idea what the voltage should be ? And okay, I’ll do the head gasket test. Thanks, I’ll report back.

Sensor should have 5 volts.

Switches have 12.

You are welcome.

Roy

I got it ! Fans are kicking on with the switch plugged into the radiator. I really appreciate the help! Btw. There was no voltage at the switch. One wire cut about a foot from it. Thanks again guys!!

You are welcome.

Always glad to help.

Roy

Four cylinder four wheel drive automatic 130,00 miles.

Coolant fans not working, both fans do work if air is turned on. Does this point to any particular fix for coolant fans not working ? I do not know which fuse or where they are located, for coolant fans. I see fan number one is first fuse/relay box closest to battery, and in next fuse/relay box fans two, three and air relays. Do not know which are fuses and which are relays ? Would truly appreciate any help. Not familiar with auto repair but am trying. Thank you.

Below is the relay. It is a small box type.

Below are fuses. There should be number markings on the top like 5A or 5, 10A or 10, and so forth. Replace only with the same number. (5A as "A" stands for amperes)

Suggestion: Try checking the ECT (Engine coolant temperature) switch for electric cooling fan located at the bottom of the radiator. (either left or right side). With the engine OFF, unhook the wire connected to the ECT switch. Now turn ON the engine, if the fan runs, then maybe it is the ECT switch. You need a new one pictured at the bottom with the O rubber ring.

Car started overheating changed the thermostat and radiator.I noticed that the cooling fans were not coming on.Wife says she noticed it about the time car started to overheat.Both motors on fans work I made jumper to battery.Changed 30 amp fuse links and 1 relay inbox beside battery. Both fans work when air is on now but radiator fan doesn't come on by it's self when you start car with air off.

Note round silver fan motor relays in fuse block seem to be very warm at times

When you turn the ac on the fans are suppose to run as well when you put the window defroster. The rest of the time the are off until the temperature reaches a certain temperature. you should have two fans. the problem could be in the temperature sending unit for the fans. With the fans running check to see if one or both are making a noise to see if one or both motors could be going bad.

1995 toyota camray. 4cyl. the radiator fan doesnt work. Had to replace new radiator but fan will not work.

Probable causes here could be the fan motor, fan relay, engine temperature sensor/gauge switch and computer-

More than likely the fan relay is bad. It should be located near the fan. If you follow the electrical leads from the fan, they will lead to the relay. They are generally around $20-$40 and are a simple clip in and maybe a bolt to reatin it for replacement.
Let me know if that helps.

I have a 95 Toyota Camry - 4 cyl DX. The radiator cooling fans are not coming on. I flushed the radiator and tested the fan switch and it is working fine. It opens up at about 205 degrees. The coolant sensor is also good - it read about 3500 ohms at about 45 degrees (cold car). I also tested the 2 relays associated with the fans (the main and fan 1). They were also good. As the temp increases I can disconnect (essentially open up) the fan switch wire and the fans will run. Also if I leave the switch wire disconnected the fans run when I start the car as well. But once I hook up the wire from the fan switch to the control it does not come on (essentially a short). Any help would be appreciated. Thanks Kevin

[quote:bf63dc3011="KEVAUG"]Engine problem
1995 Toyota Camry 4 cyl Front Wheel Drive Manual 242000 miles
----------------------------------------------------------------
I have a 95 Toyota Camry - 4 cyl DX. The radiator cooling fans are not coming on. I flushed the radiator and tested the fan switch and it is working fine. It opens up at about 205 degrees. The coolant sensor is also good - it read about 3500 ohms at about 45 degrees (cold car). I also tested the 2 relays associated with the fans (the main and fan 1). They were also good. As the temp increases I can disconnect (essentially open up) the fan switch wire and the fans will run. Also if I leave the switch wire disconnected the fans run when I start the car as well. But once I hook up the wire from the fan switch to the control it does not come on (essentially a short). Any help would be appreciated. Thanks Kevin[/quote:bf63dc3011]

Hello !!

the cooling system on these cars is a little complicated, they use a micro-computer to controll the fans, also there is a pressure switch on the a/c line that controlls the fans also, but, if you disconnect the temperature switch and the fan works that means that your problem its the thermoswitch, check it good, it should be "open" when hot and closed when cold.



good luck!

I drained the radiator, pulled the thermo switch and paced it in a pot of water on my gas stove.
I took my ohmmeter and saw that it was closed up to about 200 to 205 degrees at which time it did "open" up.

I dont think its the thermostat because as the car warms up from cold I can see the thermostat kick in.
I can drive the car about 25 minutes before it starts to overheat.

[quote:f94c793983="KEVAUG"]I drained the radiator, pulled the thermo switch and paced it in a pot of water on my gas stove.
I took my ohmmeter and saw that it was closed up to about 200 to 205 degrees at which time it did "open" up.

I dont think its the thermostat because as the car warms up from cold I can see the thermostat kick in.
I can drive the car about 25 minutes before it starts to overheat.[/quote:f94c793983]

ok, if you disconect the wire from the thermoswitch and the fan turns on that means the switch its not "sensing" the temperature, everything else its working the way its supposed to....

did you "purged" the air out of the system?

i mean, it could be a pocket of air in the system and the thermoswitch didnt work with hot air, it needs "hot water' to open...

disconect the top radiator hose (from the radiator) and pour on it "hot water" to open the thermostat and let the air out of the engine...

I`m sorry if i insist but I really think that the problem its there..

let me know!

Hi - I disconnected the upper hose and poured boiling water into it. It filled the hose and then
when down a bit (I assume because the thermostat opened up).
I have never replaced the thermostat. I know when it warms up the temp gauge rises and then levels off in the middle so I just assumed it worked.
Maybe I should just replace it. Is there an easy way to test it or is the hot water trick enough.
If so could it possibly be my water pump?
I dont see any leaks but maybe the impellar is broken
or free spinning?
Thanks for all the ideas

Coolant is lost, top of radiator is hot but coils are still cool. removed hoses and blew air through radiator passes okay so does not seem blocked.

I would suspect a bad engine coolant temperature sensor and possibly a stuck thermostat. That sensor sends a signal to the computer which the computer uses to judge when to turn on the fan(s). The thermostat could have gotten stuck after the car overheated, as sometimes the shaft of a thermostat will bend when the car overheats, causing to be stuck in place.

I am attaching Toyota's instructions on how to test the coolant temperature sensor in the images below. You will need a multi-meter or ohmmeter for this. A decent multi-meter can be bought for $15.00 to $20.00 (last I checked, at least). You will need to set it to Ohms and go from there as outlined below.

Thanks Heyman1140 for your response. i already replaced the thermostat and ran the car for forty five minutes it ran fine, fans came on and off okay with AC in on and off settings. thanks again.

Oh that is great. I am glad it was a simple fix for you. Please feel free to come back any time.

1993 Toyota Camry 2.2L.When I disconnect the temp switch on the bottom of radiator the fans won't run it has to be unplugged and then the both run on high it sounds like.I have checked all the relays that are for the fans and there OK.The fuses also look all right.I have to get it smogged now so I have to trouble shoot this problem fast.So if anyone knows anything I could do now please let me know.Thank You

it is normal for the fans to run on high when the cooling fan switch at the bottom of the radiator is unplugged,does the switch screw into an aluminum adapter that screws into the radiator? if so try to remove the adapter and screw the switch directly into the radiator.the adapter insulates the switch to much and can cause your symptoms.also on this car the coolant temperature switch is on the downstream side of the thermostat and a faulty or stuck thermostat could cause this issue to because the hot coolant can't get to the sensor.

Thank You for answering my problem. I don't think it has got hot enough to even open the switch,I put a 180 thermostat in it maybe it needs a 210 something like that I understand it has to be 200 or better to open the temp switch

your welcome and yes I think the 180 may be to cold.let me know how it works out.

I have had a problem with my cooling fans on my car.The sensor that is in the bottom of the radiator I have two different operational theorys,is the sensor when the coolant in your vehicle gets hotter is there suppose to be resistance in when it gets hot or cold,does somebody know for sure a right answer I would appreciate it.And about the relays when testing them I did not know they had two different types normally closed,normally open one will have continuity when power is applied one will not.I would appreciate any help.If the car is not getting hot enough to open the sensor I should get a higher temp sensor maybe a 210 would that make sense.

Two different system is used by Toyota for their vehicles where cooling fan circuits are concerned. For the cooling switch attached to the bottom of radiator, the sensor is open and when heat increases, the switch contacts to make a complete circuit.

The other type utilises a switch near the thermostat housing and this switch is closed all the time until the correct temperature is achieved whereby it would open the circuit causing the relay to start the cooling fans.

Both system uses different types of relays so make sure you get the correct relay.

I have posted this problem before but since then I have put a new switch on the radiator,new sending unit on motor,and I got a almost brand new radiator still not working.I was reading a article on 4 terminal relays and it said check one of terminals check continuity to ground, and I am talking about where the relays plug into in the distribution box can someone tell me what that means am I suppose to have continuity there or not and I think they was talking about terminal 3.So what does that mean and how many volts should there be in the other ones .

i t means you take an ohm meter and probe where the terminals go into box and one on ground and see if you have continuity or the ohm meter should go to zero. see pics then after checking this go to repair/electrical how to check a relay on our site. If that doesn't fix it take to a pro because I may be beyond your ability.

it was the relay thank you

you are welcome

I have posted this problem recently.My cooling fans don't come on I have the temperature sensor unplugged,so they work when you plug it in they quit.I have bought a the sensor that goes in bottom of the radiator and the one that is on the motor.So does anybody have any other idea's that could possibly be wrong ;I have checked the relays and they were OK;What else could it be?Thank You

Unplugging that sensor is a really bad idea. That will cause your fuel mixture to go full rich. The fan circuit is pretty complicated with 3 separate relays so you need someone with electrical knowledge to troubleshoot it for you.

Thank You for the schematic the sensor that I have unplugged is the one at the bottom of the radiator

Unplugging that won't make the fan come on. Grounding that wire should put it on.

Hey I really appreciate the help.You said grounding a wire will more or less fix the problem,what wire do I ground?And again thanks so much my smog is due I have till the end of the month but with these fans running on high that might make a difference but I need to get them fixed anyway

Let me add something else but that is why the fans are running now I have that switch unplugged,when I plug it in they stop.I still need to drive.

The switch in the radiator works by supplying trigger ground to the relay and turning the fan on. It should be inoperative when unplugged.