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How to Wire Trailer Lights

Shashank Nakate
Lights should be installed on any trailer for safety while driving. Know how to wire trailer lights.
Wiring a trailer light is easy and can be done without professional help. The tools required for this purpose are a crimper, test lights, a trail light connector, a heavy duty flasher, wiring kit, and an electrical tape. After gathering all the necessary materials, the process should just take a few minutes.


Before starting off with the activity, one should check whether his vehicle has a 4-wire receptacle or any other type. The 5-wire receptacle would need a trailer light converter. It can be obtained from a nearby automobile store.

Basic Methodology

In order to connect the wires correctly, it is necessary to know the color code. The colors used in the color code are yellow, white, brown, and green. The yellow color denotes the left turn signal, while green is used for the right turn signal. Brown color is associated with the parking lights, and white is used to denote the chassis ground.


  • The first thing one needs to do in the process, is to locate the harness of taillight wiring of the vehicle.
  • The second step is to find the spot for the hookup place. It is necessary that the harness be long enough to reach the connector receptacle of the trailer. If the length falls short, purchasing a new connector remains the only option.
  • One should clean the chassis of the car so that it can be used for the test light. Its clip end is used in this case. The test light is used to probe the wires.
  • Next, the headlight can be turned on to check the parking lamps. The test light comes into action at this point to check the wire.
  • Continue checking until the lamps light up. Once the signal is received, the brown wire can be connected to the quick connector.
  • After checking the parking light, the headlight can be turned off.
  • The right turn signal should be checked after this. The same process, as in the previous case, is repeated to test the right turn light.
  • The wire that is tested here is connected with the yellow one. After connecting it properly, the ignition should be turned off.
  • In this step, the left turn signal is checked and then wired properly.
  • In order to proceed, the ignition should be turned on and kept in the run position. The left turn signal needs to be activated and the wire should be tested.
  • The one which passes the test, i.e., which lights up the test light, is the left turn wire. It is then connected to the green one.
  • The last one, which is the ground wire, is connected to the white. The connection can be done with the help of a sheet metal screw.
With the completion of these steps, the process of wiring a trailer is completed. These instructions would come in handy for those who want to carry it all by themselves. It is essential that we follow these steps and help to prevent accidents.