So I have just put in a new radiator and swapped all the hardware on the radiator in the process. The electric fan has never come on while driving even while the coolant got really hot or when turning on the AC. While I had the fan assembly out I did hook it straight to the battery and it works. I also tried to bench test the temp sensor that screws in to the radiator but never got a reading on the multimeter. Since I could only heat the water it was in to 212 F (boiling) not sure if this is hot enough to get it "activate" and create an closed circuit assuming that's how it works. 

 

How hot does the temperature need to be to get a reading?

 

I am more suspicious of the relay. Not really sure where to find it. 

 

How do I test if it is the relay?

 

Any other additional advice?

 

Thanks! kmpdx

Edited March 13, 20179 yr by kmpdx

That fan should come on before boiling temp. I would replace the sender/switch that goes into the radiator, those are pretty cheap.

It's about as simple a circuit as it could be. Ignition-switched power to the fan (not sure where the relay is), ground side goes through the temperature switch on the rad.

 

With the ignition on, you should have 12v+ at the fan, regardless of coolant temperature. Temperature switch is probably set to 185* or so. If you don't have continuity across it at 200*, replace it.

OK. Thanks.I will start with the sending unit and will also confirm that there is 12v at the harness. I will report back with results although it may be a while.

Thanks again,

kmpdx

So I have 12v at the harness (actually, 11.94v, is that weird?) I was thinking of going with an aftermarket adjustable temperature fan switch. Anybody used one?