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Discussion Starter #1
Hey guys. It's been a while since I've posted here, but I've got an issue that has been a continual source of frustration for several months. The problem is that my radiator fans aren't always spinning when they're supposed to, and some days, like today, they don't spin at all. The problem is intermittent, so that leads me to believe that there is possibly some problem with the wiring, but I have yet to find it.

I also feel it prudent to note that literally the only parts of the cooling system that have not been replaced are the hoses and the heater core. I have also bled and re-bled the system several times, and it made absolutely no difference. Any suggestions?
 

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You could try disconnecting your coolant temperature sensor then start the car. Both fans should run at full speed. If one or more do not turn on at all, then the fans are at fault and should be replaced. If they turn on, but do not run at full speed, or go off and on, then some deeper diagnostics will have to be done.
 

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You could try disconnecting your coolant temperature sensor then start the car. Both fans should run at full speed. If one or more do not turn on at all, then the fans are at fault and should be replaced. If they turn on, but do not run at full speed, or go off and on, then some deeper diagnostics will have to be done.
I did not realize it could be diagnosed that way. I will have to try it, and I'll update you on the result.
 

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Discussion Starter #4
Alright, I have results, and I'm not sure what to make of them. I unplugged the temp sensor and started the car, and the fans did indeed spin up to full speed. So if I'm understanding correctly, that means it's either the sensor or the wiring for the sensor, right?
 

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Alright, I have results, and I'm not sure what to make of them. I unplugged the temp sensor and started the car, and the fans did indeed spin up to full speed. So if I'm understanding correctly, that means it's either the sensor or the wiring for the sensor, right?
So it means your fans are working. Next thing I'd check are they relays. Swap the low speed radiator fan relay with the high speed one and do the same check.

Then I'd try wiggling any wires going to the fan assemly while they're on. Just be careful. If the fans are still working then I can only see it being the coolant temperature sensor or the PCM.

Does the temperature gauge behave normally?
 

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Discussion Starter #6
So it means your fans are working. Next thing I'd check are they relays. Swap the low speed radiator fan relay with the high speed one and do the same check.

Then I'd try wiggling any wires going to the fan assemly while they're on. Just be careful. If the fans are still working then I can only see it being the coolant temperature sensor or the PCM.

Does the temperature gauge behave normally?
The gauge does behave normally. The sensor is also basically brand-new, but I also have really bad luck with things like this, so I could have ended up with a bad one.
 

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If it is behaving normally then the PCM should be getting a signal from it. The PCM detected no signal when you unplugged it and ran the fans so I'm thinking both of those are fine.

If the relays are good then it has to be a wiring issue. Possibly shorting inside the fan assembly itself. Mine just did that and melted some plastic so only my a/c fan is working right now. These fan assemblies are really crappy.
 

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Discussion Starter #8
Another update: I just checked the codes on my car, and found that apparently, the input for the temperature sensor is not within acceptable voltages. Would this be from a wiring fault, or something else?
 

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Just wanted to say, I just installed my new radiator fans and the 3-hole pigtail from the relay that connects into the RFI module on the fans wasn't making a good connection and I experienced pretty much what you described.

I had to splice a new pigtail on from my old fans, I cut the pigtail for the A/C fan and temporarily used some wire nuts and it seems to be working. But if the tab on that connector breaks off, it can slide out pretty easily, or not make good contact. I'd look at the RFI module itself (could be shorting like mine did) or that pigtail.
 

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The RFI unit on the fan shroud can go bad and cause no low speed operation. Highspeed operation generally only happens in extremely hot operations.
 

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The RFI unit on the fan shroud can go bad and cause no low speed operation. Highspeed operation generally only happens in extremely hot operations.
For me, the driver side fan did not work at all when my RFI module shorted out. When the resin inside melted, it damaged my harness connector. So when I put the new fans in, they would work on and off until I spliced the new connector in. Fortunately, it's an easy fix.
 
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