The cooling fans in my car are not coming on. I checked the relay and fan motor and they look fine. I was planning on changing the coolant temp sensor but I could not find it. Searched through the archives and found out information about the location of the coolant temp sensor, but then I also saw a thread talking about a thermo switch on the radiator that controls the fans. My helms manual does not mention this sensor. The fans run when I turn the a/c on; so I assume the motors are fine. The fans are not coming on without the a/c; is it the coolant temp sensor or the thermo switch.

The cooling fans in my car are not coming on. I checked the relay and fan motor and they look fine. I was planning on changing the coolant temp sensor but I could not find it. Searched through the archives and found out information about the location of the coolant temp sensor, but then I also saw a thread talking about a thermo switch on the radiator that controls the fans. My helms manual does not mention this sensor. The fans run when I turn the a/c on; so I assume the motors are fine. The fans are not coming on without the a/c; is it the coolant temp sensor or the thermo switch.

 

Knowing the model and year of your car would help.

When the fans do not come on, does the temp gauge rise?

Knowing the model and year of your car would help.

When the fans do not come on, does the temp gauge rise?

 

 

 

I'm sorry. Its a '98 outback limited 2.5ltr. The temp gauge does not move to hot that often, but it does move.

I'm sorry. Its a '98 outback limited 2.5ltr. The temp gauge does not move to hot that often, but it does move.

 

There is no rad switch on your car, just one coolant temp sensor that sends info to the ECM which in turn uses it to monitor the fuel trim, activate the temp gauge and turn on the main fan.

If the gauge moves to hot when the fans do not come on, I would interpret this as a sign the coolant sensor is working.

You could replace it anyway since it's cheap and will at least get that possibility out of the way.

The fans are activated by a series of relays situated in the black box just off the driver's side wheel well in the engine compartment (next to the battery). The exact function of each relay is inscribed on the box cover.

There is one relay activating the fans when the AC comes on - this one seems to be operational - and one activating the main fan when the engine gets hot. Maybe this relay is at fault.

Since you say both fans come on when you turn on the AC, I would presume the fans fuses are ok.

Hope that helps a little.

Thanks, I changed the coolant temp switch yesterday; haven't gotten the car hot enough to see if the fans come on. The temp switch on the dash did work, but it didn't go towards the hot end; even when I felt the coolant should have been hot. I switched the relays around when the A/C one worked. I replaced it with the one that was listed as main fan, and the fan stilled worked with the a/c on; so I assumed the relay was good. Will get it hot today to see if fan comes on.

 

 

thanks,

 

curtis