Computer is new, fans work and the relays have all been replaced. No check engine light! Other than a short the temp sensors are the only other culpritfor why the fans will not switch on when the temp gets to 220 degrees correct?

 

Is this the temp you're reading with a scanner? Or are you going by the gauge?

 

Wow that wa quick! I'm going by the guage. I tested the fans with a test wire just to see if they come on and they do and since I had this problem with my old pcm I figured once I got my newone from PCMforless that they would work. Not so! So I put in all new relays and checked the fuses to make sure there was no problems there. All good to go. Fans do not come on at all when everything is plugged like it should be and car is running.

 

Does it go past what you believe to be 220? I know on mine, when it's reading 160, my datalogger shows about 145. Your gauge may not be completely accurate.

 

I don't have a scanner so yeah I'm going by what the guage is telling me. I'll have to get into it a little more I guess.

 

Pull the plug from the temp sensor, the one for the PCM, not the one for the gage. Short the two leads going back to the PCM with a 70 to 100 Ohm resistor (Radio Shack). This simulates coolant temp over 230 degrees and the PCM should turn the fans on. If not check the wires to the PCM, especially at the PCM connector.

 

Hi, Im new in the forum but i saw this topic and i seem to have sort of the same problem, i have a 94' z28 that runs pretty good, when i turn the air conditioning on, the temperature stays in the middle, but once i turn it off the temp starts to go up and the car is running fine, it almost reaches the line before hot... any help would be grateful, i think it might be the temp sensor...

 

If the fans work with the AC on, it means that the fans and fan circuitry from PCM to fans is OK. The temp sensor, or wiring between temp sensor & PCM is probably bad.

 

Found my prob! Sensor wire was cracked and didn't look like it was making proper contact. Fixed!!

 

Well i turned off the a/c to see if the fans turned off and they did after life 30 seconds, it looked like they were supposed to that and then the temp started to go up... im thinking that it might probably be the temp sensor...