Engine cooling fan switch

[DonDDR]

Fans dont come on and I cant find the switch in the radiator. Granted its cold wet and kinda dark out. Looking for a little help so I dont have to climb around in the wet.

TIA

 

[jimtash]

It's in the black box located on the radiator support. It's called a CCRM and contains the fan relay. You need to replace yours with one that has the same code.

 

[DonDDR]

Thanks Jim.

 

[jimtash]

You're welcome.

Here's a simple test to determine if it's the relay or the fan motor itself. Disconnect the coolant temp sensor located in the crossover tube on the rear of the rear head while the engine is running. That causes the fan to automatically kick on. Take a test light and probe the red power wire in the connector going into the fan motor. If you have juice then the motor is bad. If not, the relay in the CCRM is.

 

[rubydist]

I have also had good luck testing by giving the ccrm a small-ish whack with a medium sized wrench. often a stuck relay will then pull in. in some cases, it will actually function normally for a good while before it gets stuck again. in some other cases, it won't.....

 

[DonDDR]

You're welcome.

Here's a simple test to determine if it's the relay or the fan motor itself. Disconnect the coolant temp sensor located in the crossover tube on the rear of the rear head while the engine is running. That causes the fan to automatically kick on. Take a test light and probe the red power wire in the connector going into the fan motor. If you have juice then the motor is bad. If not, the relay in the CCRM is.

Jim, thanks so much for your reply and info. Very much apperciated. But I cannot find the crossover tube. I know my old 5.0 Mustang has the crossovers behind the heads at the fire wall. On the SHO, I dont see anything like what I think to look for. I do see the temp switch for the gauge but i suspect that is not what you are directing me to. I can jump the fan motors to see if they work easy enuff but I like your system check much better. As in what if its both or neither. Jumping the fan motors, IMHO, wont give me results like your test. But doesnt this fan cooling system automatically turn on the aux fan when the climate control is set to cool? Or does it not come on if I am out of of refrigerant and the system is not working correctly? Thanks again for your help.

 

[rubydist]

its perhaps not the best description of what to look for - on the rear of the engine, there is a spider-like arrangement where the thermostat mounts. toward the firewall from the thermostat is a 2-pin temp sensor which the pcm uses to determine engine coolant temperature. this is the connector that jimtash is suggesting you unplug. that sensor tends to be buried behind a bunch of wiring, etc. so you might have to search for it.

 

[DonDDR]

I dont see anything that looks like that. I am a pretty smart guy and understand what you and Jim are telling me but.... I am asuming the thermostat housing is at the end of the top rad hose where is connects to the motor. Looking back twards the firewall from there, on the left or drivers side of the motor I dont see anything that relates to the cooling system or sensors as you describe. Thank you much for your reply and I must be missing something simple.

 

[jimtash]

Look at the lower center of this pic and you see two connectors side by side beneath the plug wires. Behind that area is the coolant temp sensor.



This is what you're looking for:



The sensor is at the top.

 

[DonDDR]

Jim, you rock, after looking at the 2nd picture, I went to the car and found it right off. Thanks very much. And whats with the first picture? Looks like a SHO motor in the back of a old Lotus or something. Do tell,

Thanks for the repiles. Much apperciated.

 

[jimtash]

Just a random pic off Google. The only one with a good view of the rear.