I am rewiring my existing electric fan setup. I know that if you run a wire to pin 1E on the ECU, it will raise the idle when the fan comes on. I have the wire on the pin already, question is, does it need to be going to the fan's positive or negative wire?

 

It's pin 1E for s4 and pin 1O for s5. That's the A/C input pin. So when your fan comes on, the ECU thinks you turned on the A/C.

It should be connected to a switched ground which is activated when the fan turns on. Where you get that ground depends on how you wired up the fan and the relay.

 

I was just reading your write up on this... I have a cheap-o autozone controller, the kind with the probe and adjustable temperature switch. The controller has two outputs, one goes to fused 12v switched, the other to the positive of the fan. The fan is grounded to the body. It works incredibly the way I have it now, it just bogs down my idle way too much when I'm sitting still.

 

That's not enough information to answer your question.

 

I don't see how, but I'll figure it out. I just have to reconfigure the fan to use a switched ground instead of switched positive.

 

If you are controlling the fan with a switched ground then tap a wire into the ground side of the fan and run it to pin 1E.

 

That's what I ended up doing. However, when I tested it, it did not raise the idle. I guess my BAC is shot.

 

clean it