Hey guys. I am trying to wire a switch to turn the fans off. I have a DFI which is very voltage sensitive. If the fans start up when I am trying to start car, not enough voltage to kickstart the computer.

How would I wire a switch to turn off the fans? Could I just put a switch leg on the wire coming from the sensor in the head?

 

anyone?

 

That should work. I'd use a normally closed momentary switch to interrupt the circuit...that way you don't forget to 're-arm' it manually and let it idle for an extended period and consequently overheat.

Idea #2...wire a switching relay up to interrupt the circuit while cranking. That'll do it automatically for you.

Pete

 

switching relay sounds like a good idea. but where do you put it? I am thinking on the fan relay itself, but which wires? just the positive lead?

 

all you would have to do is put a switch inline with the black wire that goes to the fan switch in the block. a realay is not necessary. i know this works with my car (1988 tbi) good luck

 

Lessee...you'll need a relay that has a normally closed (NC) terminal in the neutral (unpowered) state.
To operate the coil side of the relay, you could tap into the purple wire on the starter terminal, and run the other side to ground.
On the switching terminals, the common terminal can go to the switch in the head, and the NC terminal would go to the fan relay.

This way, power is able to flow through the relay any time except when the starter is being cranked.

Pete