"Are you using your headlamp high beam function to activate the relay or your fog lamp switch?"
Matt400,
I have the relay drawing main power from the battery, the fog light switch (not OEM, looks like regular old on off switch from your favorite parts store) in cab draws power from "spare" ignition powered space in fuse block to energize relay, did not wire into any headlamp wires like the instructions said to do. The instructions said to tap into the low-beam wire. That would have taken power away when I turned on the high beams. I used the Mopar fog lights and wiring harness since my truck was not ordered with them initially. I wired them (fogs) that way so I can either; turn switch on and leave it on (lights turn off when ignition is shut down--poor man's daytime running lights) or turn fogs on/off while ignition is on. I have been known to leave fogs on all night long so this set-up works great for me. I did not have to buy the "Britebox" this way. Unfortunately, if your truck came with fog lights already installed and your fog light control is on the headlight switch, I think you wil need "Britebox" or equivelant.