It was hooked up correctly and like I said tested on the bench and it worked fine. When it was installed on the truck I even tried running a jumper to ground in place of the horn switch and that didn't work either. I have done automotive electrical work for decades so I have a fairly good idea what I am doing😉. Hooked up on the truck exactly the way it was on the bench, the only difference being it was grounded through the mount to the engine. Now it no longer works not even on the bench???