Can someone PLEASE tell me where my horn relay is located in 88 Mustang. I have rebuilt almost everything on this car, and I cannot find anything that even looks like it.
8.4 in 1/8 mile w/ no turbo,supercharger(yet) and no bottles.

 

This must be your lucky day. I have an 88 GT and I disconnected the horns and removed them when I took it off the street to make a full time racer out of it. Just this past Saturday as I was sitting in the car waiting for them to call us to the lanes, I pushed on the horn button and heard the relay clicking under the dash. I suggest you unplug your horns and try this to see if it makes the clicking sound so you can find it. I know there is a big relay under the dash on the right side of the steering column because I pulled one down from this area and kept bending over the plugs until I found the one for the damn door open chime and then I put it back up where it came from. this might be the same one for the horn, I just don't know for sure. it was about 1/2 thick and 2" square and had about 10 connections going to it, so I'm sure it worked for more than just the door chime. hope this helps you out!