I am installing an electric fan, the wiring harness I bought has an adjustable relay for when I want it to come on. It's pretty simple, I dont use a couple wires because I no longer have AC. But there is a Red wire coming off the harness which goes to the + red wire on the fan, the grounds, IGN, and then there is a blue wire on the wire harness it says Second fan lead+ do I wire that in with the other red+ lead to the fan+ ?

Is this temp sensor fan?

The last fan I elped a friend put on had 2 ways he could run it.

#1 - manually from a toggle switch

#2 - temprature enabled from a temp sensor

Both modes energized a relay which actually turned the fan on.

Yeah it comes on at a desired temp under the relay. Have a blue and red + wire.

Originally posted by pnutkemist:
Yeah it comes on at a desired temp under the relay. Have a blue and red + wire. Sounds like the blue wire is positive for a second fan. If you're not running dual fans I would tape it and cable tie it out of the way.

Ah thats right, dual fans! Thanks guys... tape it off I shall.

Why not use to power a light that would let you know the fan was on?

Originally posted by DG:
Why not use to power a light that would let you know the fan was on? Or an LED, they are smaller and hardly use any power.

But this won't tell you he fan is running, just that its supposed to be, because its energised.