Does the ECU have any control over the passenger side AC radiator fan. By pressing the AC button with the blower motor on would would always kick on the additional fan. But all of a sudden it stopped working.

I've checked all my fuses. Looking at the wiring diagram it appears that there is a pin that goes to the ECU, however, correct me if I am wrong, I think this is just an input for table switching/idle adder.

If I cant figured this out soon I am going to just wire in a new relay that uses the power from the first fan as a signal and trips with the Main radiator fan, but I did enjoy my manual fan control.

Any comments, thoughts, suggestions, test procedures, and even snide remarks will be appreciated.

 

The same relay the turns on the compressor turns on the a/c fan and main fan. If the a/c fan is failing to turn on, then the a/c relay is dead (easy to tell if the compressor is running or not) or the fan motor is dead (which can be tested using TFA to GND).

 

I did do the TFA and GND jumper however it only turns on main radiator fan. I did check the AC fan with a 12v power supply and it did turn on, so I know the motor isnt dead.

I was under the impression that the relay for the AC fan was on the passenger side near, wrapped in rubber, the headlight motor and that the main fan relay was on the driver side behind the black panel.

I don't have an AC compressor so its not as easy to just look and see, but I may browse around and just meter everything and see what changes when the AC button is depressed. It could also be the AC switch in my HVAC unit has gone bad, but I haven't gotten that far yet.

 

correct. sounds like the relay is bad.

 

That makes sense. I just measured continuity across the fan wires and it shows there is contact over the power and ground leads to the fan lol.

Whats odd is i cant find the wire that switches to trip the relay based on the position of the AC button.