Black331Stang said:
cool thanks...and timmy when your talking about "posts" u mean on the switch right? but i dont think u stated where to put the relay. thanks
if you have your switch set up so that it is only on with the car (as Jerry mentioned. Jerry, glad to see you in here

, you are in biz. if not, find a wire in the fuse box, etc that is only on with the key. dont worry about draw, as this wire will only need around 150mA to trigger the relay. hook this wire to the switch on the "power" terminal.
now find where you want your relay (i have some around the windshield wiper motor, , but its your choice, as timmy mentioned. closer to the fan is always better, IMO.
now find the wire that you have now running from your switch to the fan. this will be your trigger for the relay. cut the wire where your relay will be.
there are several ways to wire the relay, but this is one way that works if you dont understand how they work.
hook the cut wire coming from the switch to terminal 85
hook the other cut wire end (going to fan) to terminal 87
hook a ground wire to terminal 86
hook battery juice (run a wire from the hot side of the starter solenoid -side with all the wires connected to it- with a FUSE, to terminal 30.
make sure that your wire from the relay to the fan is the correct AWG (gauge). same for the wire going from battery (solenoid) to the relay and the ground wire. cant go too big with a ground wire, IMHO. these wires supply the relay, and thus fan, with power, so you want full juice getting to the fan.
there are also ways to wire it so that the fan comes on with the a/c. basically i would tap into a wire that is hot when the a/c is on, using that as a trigger for another relay, which has output going to the fan.
as for the 2 speed fan, as i recall, Jerry runs his at low speed and seems to do fine. for simplicity, i would probably use a secondary temp probe to energize a relay to turn it to high speed. but im speculating, as i dont have experience with 2 speed fans. i would wire it to low speed, and if that doesnt cut it, just connect to the high speed wire instead. simple.
and if you are uncomfortable with this, the premade harnesses can be nice, though i am imagining that you will have to do some wiring anyhow to make it how you like.
hope this helps a little. good luck.