I installed a new set of Rigid Industries Dually LEDs on my grille guard and they came with a nice preman wiring harness.

I wanted a key-on hot only connection instead of going to constant 12 volt supply.

I went to the relay/fuse box in the front of the engine compartment and there was only one empty slot with a key-on hot opening. What gives?
Manufacturers used to leave a couple of these type slots open for accessories. This slot was for a relay, so I had to modify a large soderless terminal to fit the slot for now.

Am I looking in the right place for the power source I want?

I know I could have tapped into the factory fog light circuit, but I wanted the ability to run these off road lights with my high beams.

 

you might think about taping into trailer plug, you would be hot only when your lights are on,,

 

where would I be able to tap into that ciruit?

 

I used the trailer brake harness under the drivers dash.

Its fused at 30 amps - far more than you need, and its key on hot.

Easy as pie.

 

Mine only come on with the high beams. I tapped the passenger side high beam circuit to drive the relay then went from the battery thru a 30A fuse to run the lights.