Finally got everything mounted and wired up tonight. I have one glitch that I need to work out. I wired the compressor relay to energize with upfitter switch #3 (the wire runs from the upfitter switch to the pressure switch on the tank, then another wire runs from the other side of the pressure switch to the relay). I also wired the air horn relay to upfitter switch #3. I tapped into the stock horn ground wire coming from the steering column. Switch #3 energizes a relay, and pushing on the steering wheel horn button grounds it, thus sending power out to the horns. I did it this way so that the air horns could be turned off if necessary, and so that only the electric horn sounds when locking the truck with the key fob. Here is where things get interesting; when the tank is not full, and the compressor is not running (key and or upfitter #3 off), the electric horn sounds constantly. If the tank is full, or the compressor is running, the electric horn works normally. Any idea what would cause the stock horn to sound when the pressure switch is closed and there is no power running through it?
I may end up tapping into the hot horn wire to activate the relay. I think this would fix my issue.
Anyhow, here are some pictures of the install. It's not easy to take pictures from under the truck, but ya'll will get the idea.
The tank and compressor are mounted on the passenger side frame rail, under the rear door.
The horns are mounted on the driver's side, under the front door. They would not fit on the passenger side due to the mounting of my transmission filter on that frame rail.
