Hi, I have a 40 1/2 ton that I have restored. I made the wireing harnress by following what was already there. there was no horn or headlight relay mounted anywhere on truck. I did not know that they existed until I was reading a catalog of parts. I am presently useing the horn wired hot. The headlights are also wired hot with a fuse on the lightswitch. My question is do I need them and what do they do? If so how do I hook them up? Any help would be appriciated. Thanks Gerry
