Cooling fans not working!!! Bad ECT Sensor??

[lexanthon]

I have a 1998 accord LX 4 cylinder. I have noticed that neither cooling fans will engage. I changed the thermostat thinking that was the problem and that didnt work. i tried jumping the fan switch on the thermostat housing and they still did not come on. i have been researching to find a solution to this problem with no success. i cant run the ac without the fans because it begins to boil over the radiator overflow tank. i have read something about the engine coolant temperature sensor being bad would maybe cause the fans to also not work properly. where is that located and how do i check to see if the sensor is bad? any info would be greatly appreciated.

[GhostAccord]

It could be the coolant temperature switch, or it could be the fan relay or fan control module.

The fan switch, is located in the thermostat housing. To test it you need to check it's resistance. As the temperature of the coolant goes up the resistance between the two contacts should go down.

If you pick up a Haynes manual it will have all of the testing procedures for the above mentioned components. I have the manual here, unfortunately I don't have the time to type out all of the steps for each component.

[nus_dogg]

It can't be a bad ECT; otherwise, you'll have a hell of a time getting your car started as the ECU will be seeing -40 from the ECT and be dumping hella fuel to get it to start.

[sublime423]

First off lets "keep it simple, stupid!" before you go doing all these checks let's look at the simple checks first. So, both fans don't work? will they come on with the A/C turned on? If yes, you got a bad fan switch, if no you got two bad fan motors. Now let me back up what I am talking about with another quick check. lets say you turn the ignition on (key on engine off) A/C off as well the fans should be off. Disconnect the fan switch which is on top of the thermostat housing it is a two pin connector take a thin and I mean thin paper clip and make a "U" and make the two terminals touch (you don't need to JAM the paper clip into the terminals just touch them together)....this is "jumping" the switch. If the fans come on that will back up the bad switch theory and if they dont I'm saying fans. One more check then I'm out. Plug the fan switch back in and start the engine turn the A/C on. No fans.....take a something and smack the fan motor like a screwdriver or small hammer a couple of times (you are not trying to knock it out the park, just knocking on a door strength) sometimes this can jar a bad fan motor in to working for a short time. If they come back on you must realize that they still need to be replaced. Ok some can say fuses and relays and PCMs and waternators. checking all fuses is not a bad idea but the fact is the fans are ran off different fuses and relays to keep one fuse or relay from shutting down both fans at the same time. If you do all this and want to be for sure here is one last check if you have a Test light, disconnect the fans with the key on engine off and check for power to each fan if you got power check for ground if those check out you got bad fan motors.


I hope this helps.

[sublime423]

Originally Posted by lexanthon

I have a 1998 accord LX 4 cylinder. I have noticed that neither cooling fans will engage. I changed the thermostat thinking that was the problem and that didnt work. i tried jumping the fan switch on the thermostat housing and they still did not come on. i have been researching to find a solution to this problem with no success. i cant run the ac without the fans because it begins to boil over the radiator overflow tank. i have read something about the engine coolant temperature sensor being bad would maybe cause the fans to also not work properly. where is that located and how do i check to see if the sensor is bad? any info would be greatly appreciated.

Oops.....Missed that part lol!

bad ECT sensor= check engine light on. BTW the ECT sensor has no control over the fans.

[poorman212]

ok, this is a few days old, been on holiday so trying to catch up.

Wouldn't the first thing be to put 12v to the motors and be sure they are good? The OP jumped the switch. Either one (a or b) should make the fans run, as long as IF it was thermo a the key was "on".

"sublime"- you might have had that somewhere in that blob of text, I got lost after the first line or two.

[lexanthon]

thanks for all the advice!!! i jumped the fan motors to the battery and fans didnt start. i put a meter to see if they were getting power and they were. so what i did was hit the motors with a hammer and they finally engaged. i was shocked when they began to spin. ordered new motors today, but will get me through the week with ac again. thanks again!!!

[T Wgproductions]

I'm glad that I saw this today... I'm having a similiar problem.. My ac compressor, compressor fan and coolant fan won't come on.. I've jumped the fans and the ac compressor.. All of them work when I jump then.. So I ruled out the fans or compressor not working.. Since the window relay and the coolant relay are the same i swapped them.. And the windows still worked So i've ruled out the relay.. I checked the fuse in the car just as a precaution before I posted.. and still Nothing.. I don't understand wtf is going on.. And they all stopped working at the same time.. what is common in these to make this happen

*update* jumped that thermo/fan switch.. NADA .. I need help!

[poorman212]

TW- What year is this? 4 or 6 cyl?

Which underhood fuse have you checked?

[ChrisMaconGa]

ChrisB from Macon Ga here. I'm going to check an issue I'm having on a 96 and running hot. I changed the themostat. I've bleed the air very well. I turn on the car and start the ac. Only the left side fan turns on. My inf readings are 158-175.front and back..may not be getting it hot enough to turn the other fan on??

[DrJimmieRustles]

Have you tried jumping the fan to ensure the motor is good?