i am wanting to hook up a switch to manually turn on the fun when i want to. my question is, do i just splice the fan switch wire into one of the terminals on the switch and put a wire on the ground terminal to ground it? any help would work.

 

What you suggested will work. But, if you want a little less wire to run, you can run your fan switch off of the green/white wire from the coolant fan relay. The fan relay is located on the firewall in between the driver's side fender and the brake booster and master cylinder. It's in a small black bracket that holds 2 relays. The fan relay is the one closest to the driver's side fender.

Here is a bad wiring diagram I did a while back in MS Paint to show how to do it (ignore the fuse, though, it's not needed):

 

ok thank you, then would i just run the wire through the dash to my switch?

 

Does that work the same for an 86? My relay is near my coolant overflow bottle but it should be the same idea, right?

 

Yes
Yes, it will work the same. I just checked a wiring diagram for an '86 305 TPI and it's the same wire (green/white).

 

i love this site. not even 15 minutes from my first poat i got a response. thank you all very much!!!

 

nice

 

What guage wire do you run from the relay to the toggle switch?

 

Pretty much any wire will work. It is just relay current (on the order of 400 milliamps).

Anything you can buy at an auto parts store will be fine.