Back in the days, connecting trailer lights to a truck or any other tow vehicle meant a good deal of work on its electrical system and original wiring harnesses, including cutting, stripping, and splicing of wires. Today, there are aftermarket plug-and-play lighting solutions for vehicles and trailers with different connector terminals.
To connect trailer lights to vehicle, you just need to unplug the tail lamp harness and plug in the new make/model specific harness between the vehicle’s original wiring harness and the tail lamps. Such harnesses usually hook directly to car battery, eliminating the need to add extra load to the electrical system.
Some of today’s popular vehicle models, the likes of the Toyota Tacoma, Dodge Ram, Chevy Silverado, Jeep Wrangler, and Jeep Cherokee come with the available factory tow packages. If you are planning to do towing frequently, choosing a vehicle equipped with a factory trailer package is the absolute best idea. It will save you from figuring out how to hook up trailer lights, because you will have a trailer harness connector already there, in the rear bumper. Get the right harness with the appropriate connector on one end and 4-way connector to fit your trailer on the other one and you’re all set.
There are various types of connectors with 4 to 7 pins for main lighting functions as well as auxiliary functions like surge brakes and 12 volt “hot” lead. The basic lights that should work properly to make the trailer road legal are running lights, turn signals, and brake lights.
The basic connection is provided by a 4-way style plug, that allows hookup for the three major lighting functions plus has one pin for the ground wire. There are wire color codes that correspond to specific functions; wire colors vary by manufacturer and there is no one single color chart, so you will need to locate wires by function.
Apart from the basic 4-way connectors, there are other trailer plug types:
- 5-way connectors add one pin for surge or hydraulic brakes if equipped.
- 6-way connectors allow for two auxiliary functions, typically 12 volt power and electric brakes.
- 7-way connectors have additional circuit for backup lights or extra 12 volt power source.
Connections to a truck or any other tow vehicle are made easy and affordable, so all you need to do is choose the appropriate kit to get the lighting job done.