YO WILLY!
WELCOME!!
STOCK HORN Wiring Diagram in an 86
Source: by Xris
See if this is same for your Grant KIT; Post The Gran kit Number.
Installation, Grant in an 89 WITH CRUISE
Source: by Andrew K (Andy351, das panzer, sloppy seconds, the magic carpet)
http://www.supermotors.net/clubs/superford/registry/2318/72908
"...Picked up a Grant #748, 4 spoke 14" 3" dish wheel and install kit #3249
here is the cover from the installation kit. install the cover and then the bracket for the backside of the steering wheel.
here it got a little tricky, the included directions sucked. i think my wheel came with an integrated horn button, but my original horn never worked quite right anyway. i followed the directions to clip part of the wire off the horn button so that it can't ground on the steering wheel, however my horn doesn't work at the moment, i'm not sure if i did that part right. you take the horn button out of the wheel, pop it all apart to clip the part of the wire/spring that sticks out to ground against the steering wheel and then put it all back together.
pop the horn button back in, tighten the allen bolts that hold the steering wheel to the bracket..."
IF NOT SAME KIT, See WIRING DIAGRAM @