My 1987 Mustangs horn does not work. The brown relay under the dash by the door chime gets hot if I plug it in. Also my cruise has stopped working. Do these 2 problems have something in common?

 

i am not sure.. check this over, idk if you have one in you car or not, but here is a diagram of the fuse box..

https://mustangforums.com/m_5229317/tm.htm

 

IIRC, the horn & cruise are on the same fuse in the 87 (I had one, back in the day). Never had the problem of the relay getting "hot" - but how hot are we talking? On some relays, 120 degrees or so is considered normal operating temperature.

-John