This morning my horn started to sound all by itself. For now, I'm assuming the truck is not haunted, so that leaves some sort of electrical gremlin.

The truck is a '93 5.8L F350. There is a pair of aftermarket horns mounted to the left of the radiator.




It looks to me that the horns each have a power in wire that is blue. One has a yellow out and one has a red out. These both appear to be to ground. How does that work out as a circuit?




Here are pics of the common power and the blue wires (one for each horn).

Any tips on how this circuit is s'posed to work would be great. Any ideas on what makes it go off by itself would be even better.

As a note we did have a heavy frost over night, the horn started going off just before the sun burned the frost off the windshield.

Thanks in advance,
Dave