Blue electric brakes or hydraulic reverse disable see blue wire notes below in the trailer wiring diagram and connector application chart below use the first 5 pins and ignore the rest. Running lights left turn signal and brake lights right turn signal and brake lights and ground.

Curt 56033 Vehicle Side Custom 4 Pin Trailer Wiring Harness For Select Infiniti G35 G37 G25x Nissan Rogue
How does 4 pin trailer wiring work. The left and right turn signal lights should each have a different color. A 4 way trailer connector has the basic lighting functions only. Traditional trailer with brakes use a 5 pin connector. There should be a common color for both the tail lights. By law trailer lighting must be connected into the tow vehicles wiring system to provide trailer running lights turn signals and brake lights. Verify the harness color codes at each tail light.
Following the standard method for wiring a trailer connector is vital to the safety of your vehicle while towing. The remaining color is the ground wire. Cut the four pin plug off of the trailer harness. I bought a new 4 pole light kit for my car trailer and it was a v style where you run wires down both sides of trailer and i didnt like the way wires routed so i ran them down 1 sideright side problem is i cant get my side running lights to work i connected them to left side tail wiring and routed 1 wire over to left side should i have connected it to right side wiring then run it over to. Make sure that all cables are electrically conductive. One way to check for faulty wires is to use a circuit tester.
Trailer wiring diagrams trailer wiring connectors various connectors are available from four to seven pins that allow for the transfer of power for the lighting as well as auxiliary functions such as an electric trailer brake controller backup lights or a 12v power supply for a winch or interior trailer lights. Use this 4 pin trailer wiring diagram to properly wire your 4 wire trailer plug. This accounts for three of the colors in the wiring harness. Trailer electrical connectors come in a variety of shapes and sizes. A 7 way has these functions and a 12 volt circuit a circuit for electric trailer brakes requires a brake controller in the vehicle and a reverse light or auxiliary power circuit. 1 4 wire the first 4 pins white brown yellow green just like the 4 pin connector above.
Installing your 4 pin trailer wiring system is easy if you follow the correct procedure. Auto electric cooling fan wiring part 2 wiring the relays duration. If it is not no amount of wiring will get the lights to work. I had no choice but to install the wiring while my boat was on the trailer and having to work underneath my boat made the job a little more difficult but if your trailer is empty installation is much easier. The first thing you need to do is make sure that your connector works properly. The basic purpose remains the same whether your truck and trailer is using a 4 way 5 way 6 way or 7 way connector.
Automotive 4 pin and 5 pin relay explained which one. Installing 4 pin wiring on a trailer is an easy project that takes a few hours or less. How does a relay work. Connecting the wrong color wires will result in mismatched taillight functions and confusion on the road.
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