I put the Tire Minder booster in the wardrobe just beside the 12-volt wardrobe interior light, it is actually just on top of the wheel well, and it is attached to the live 12-volt feed to the light. Since I boondock quite a bit and I was concerned about having another "phantom" draw on the batteries, I added a small SPST switch, mounted into the base of the wardrobe light so that the booster can be disabled when not in use. The ground wire from the booster is connected to the negative lead to the light switch.
1987 Excella 32-foot
1999 Dodge Ram 2500HD Diesel