Cars lihgtThis pickup came with an adapter harness for the trailer hitch in the glovebox. Simply disconnect the loom to the truck lights and plug in the adapter. You'll still need to wire the trailer.
But wiring a trailer may not be easy. If you're towing just for the day and don't ever plan to tow again, you can pick up some adapters that replace the taillight bulbs in your vehicle and have pigtailed wires hanging from them. How you route the wires out of the light sockets and down to the hitch can be problematic. And what if you have a trailer with simple 1-lamp lights and a car with multiple taillights, like most European cars? At the very least, odds are the trailer and vehicle use different connectors, as the trailering industry uses at least four different styles.
Red To Green To White
Let's start with the basics. Most trailers have three circuits--for running lights, and left and right brake lights. The brake lights will flash for the turn-signal function--it's up to the flasher relay in the car to know when the brake lights are on and to flash the appropriate filament. So technically, you need only three wires to the trailer plus a ground wire.
Always run a ground wire from the frame of the vehicle (not from the hitch or bumper) to the trailer. The metal-to-metal contact in the hitch is not reliable enough for a consistent connection.
This means you'll need a connector with at least four contacts. Not surprisingly, the standard flat-style connector for trailers uses four pins, with one unshrouded male pin on the vehicle end for the ground. Other common styles of connectors use five, six or seven pins, and these are the styles you'll see installed by the manufacturers on new vehicles. Why more than four? Larger trailers sometimes use a separate circuit for running lights on the sides and front of the trailer. Some trailers use electrically actuated brakes. It's not uncommon for enclosed trailers to have interior lights or accessories powered by the vehicle battery, so that means another circuit. Dash Kit
