1999 Chevy Cavalier Horn Relay Location

The horn relay for a 1985 should be on one fender or the firewall.
Usually with a group of other relays.

the relay is under the hood behind the air cleaner box, their is a tab in the front and back of cover push them away from the cover and pull straight up, If you are standing at the drivers tire it should be the 3rd. relay in from the right and they cost about $9.00. hope this helps

The clicking is the horn relay, which should click.
It must be that the horn is bad or disconnected

before you change the pcm. check battery cable to the starter sometimes they get lose or burn brake . chek the engine fuse . its in the engine compartment.

If your horn isn't working and it isn't the horn itself the next thing to check is the horn wire in the steering wheel under the air bag. The little clip breaks off in time and the horn wire pops out. To repair you can remove the wheel and replace the part but I usually grind in a new notch in the old plastic and re attach the wire and it will work again.
Test the horn itself first. Just remove the connection to the horn and attach 2 wires to a live battery and tough the 2 sides of the contacts on the horn. If it blows the horn is good. If not replace the horn before you go any further.

the clicking noise is the horn relay, this means in most cases the horn is defective and should be replaced.

under the dash in far left top corner iis a small panel inside are the flashers relays and buzzers which are difficult to remove and install.

should be under the hood in engine compartment. have you checked the fuse?

The horn relay is located under the dash on passenger side, look careful and you'll see it.