So ive searched and read every fan thread I could find and was curious if anyone has ever ran into this problem. Keep in mind I am running a Power FC with the fans set to come on at 86C set through a datalogit. Both fans are working and do not come on until 105-107C which I understand is normal in stock configuration. While driving on the highway the temps usually dont exceed 93C so coolant/burping the system isnt the issue. So I started to swap over all fan relays located on the passenger shock tower with a good set Carx7 is currently using on his car(his fans activate at 86C and we used his datalogit to set my fan temps to the same). The problem still persists and I am stumped as to why my fans will not come on at the desired temperature set though the datalogit. Has anyone experienced something similar to this problem with a Power FC? The unit is used but ive never heard of a issue of the fans not turning on due to a faulty Power FC. I would assume the Power FC is fine if its running the car and sensor check is fine. If anyone can shed some light into this id appreciate it.

 

There is one output from the PowerFC to the fan relay. Something is funny with that output, either the wire is damaged or the plug going into the relay is bad or something.

Get your wiring diagram and trace the wire down.

Dale

 

Thanks for the reply Dale, ill try to trace it down tonight and hopefully solve this problem.

 

So work has occupied my life and I finally got around to tracing the output from the ECU and its fine. I also tested the fans following the FSM by grounding the TFA and GND together in the diagnostic box. When grounding these two together and the key in the ON position the relay clicks yet the fans do not come on. Its as if fan speed 1 is not working yet fan speed 2 is. Would this suggest the fans themselves are bad?

 

I've been having this problem for quite some time as well. Before, I wasn't even sure my fans would kick on because I never let it get that hot before I just turned on the AC to kick the fans on. My fans won't kick on until 209F/98C even though they are set to come on at 89C in the PFC. But like I said, I didn't even know they kicked on themselves until a few weeks ago because I was so afraid of it overheating if I tested it, and I didn't know until today what the exact temp was that they came on. I was content with just turning on the AC before but now I'd like to get this figured out. I figured it was a bad relay or something but maybe not.

 

You have checked the wiring between ECU and relay, u have checked the relay. So time to check the power-relay-fan wiring.