Ignition "key on" power

[ft_nox]

I'm looking for a wire under the hood that I can tap into to run an electric fan. I read the efan write-up but the bolt on the side of the fuse panel is constant power.

 

[joegr]

Let's be clear here. There is no switched power circuit under the hood that has nearly enough power to be able to run an engine cooling fan. You will have to use a relay. Power for the fan needs to come from the stud on the firewall on the passenger side. (It has a heavy cable attached to it that goes to the starter.) Wire from the stud (with a fuse as close as possible to the stud) to one of the relay contacts. Wire to the fan from the other contact. Power the relay coil from one of the switched circuit in the under hood fuse box (like the one to the ignition coils).

Don't use the "bolt" on the fuse box for fan power. The wire supplying that bolt is not heavy enough for the fan motor current.