Recently my cooling fans started coming on ( high speed) at about 180-190 deg on stock gauge. Before the engine would be about boiling over when they came on. I have a Casper Electronics fan control on it that I use at the track or when setting in lines. I ran it this morning with it disconnected did the same thing. The only thing I did lately was install a new throttle body shouldn't affect that. Any ideas?

 

Are you sure the stock dash gauge is accurate?

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I will check it out.

 

Forgot to ask... have you scanned it for codes? Some codes turn on the fans.

 

No I haven't scanned for codes I don't have a laptop to do that. That's something I need to get. I did check my gauge yesterday looks like it's reading about 195 degrees when they come on.

 

Is the coolant temp sensor in the head getting 12 volts? Is the resistance vs. temperature of the sensor in the head correct? That's what the Shoebox procedure is all about.

Stock fan programming is fans on low at 226*F, fans on high at 235*F.

Is it possible some of your add-on fan control wiring is shorted out?

 

Yes the sensor is getting 12 volts and the resistance was correct. I did disconnect the fan control it did the same thing. I am going to check out that wiring some more.

 

I found my issue. My car had a extra connector in the cooling fan wiring that had two wires coming out of it that went to a sensor in the passenger side head, it has one pin. I was checking with ohm meter wires were showing zero resistance so I think they are shorted some place. I took that out and ran it the issue is gone. I looked on the Shoebox site I didn't see that connector or sensor in any of his wiring diagrams or pictures so not sure why mine has that.