AUTO How To Troubleshoot Trailer Wiring

Your trailer’s wiring system will inevitably face certain problems over time because of wear and tear. Troubleshooting trailer wiring problems will not require a lot of equipment. Most of the time, you will only require a test light.

• Initial checks. Before trying to diagnose wiring problems, be sure to check the condition of the fuses in your fuse box. Also check the condition of the fuses for the trailer circuits. If you cannot determine whether your truck has these fuses or not, refer to your user's manual.
• Check the lamp bulbs. Inspect each and every lamp to check if the bulb is functioning. If a lamp is not working properly, simply replace it with a new bulb. These are available at auto parts stores, and are often inexpensive.
• Check the lights. One simple way to troubleshoot is by turning on the lights after connecting the trailer to your truck. You will also need to check the brake and turn lamps. Have someone step on the brake pedal and manipulate the hazard button and turn lever. Look for any light that is not working. Each contact in the trailer connector must have power whenever the corresponding light on the truck is turned on. This includes the turn signals, and the brake lamp. Take note of those broken lights and inspect each one of them afterwards.
• • Look for any broken or damaged wires. Sometimes, wiring troubles come from physical damage on the wires. Do a visual inspection on your trailer’s wire and cable system. Damage can come from wear and tear, from the elements, or even from pests chewing on your wiring system.
  • Replace blown fuses and wiring. Fuses will blow if there is any overload in the system. Be sure to carry an extra set of fuses in your trailer, so you can easily replace blown fuses. If you find any wiring damaged, you can fix these by replacing any of the sections with missing or broken insulation. Use a solderless butt connector to splice the broken ends, and replace the insulation.
  • Clean the ground wire connection. A bad ground (the white wire) can be another potential source of electrical problem in your trailer. Have someone depress the brake pedal as you check the brightness of the lights. If all of the lights are flashing, or they are too dim, it is best to have the ground wire connection removed and then cleaned.
  • Clean the lamp ground connection. If replacing the broken bulb with a new one does not resolve brightness problems, you should also look for the lamp’s ground connection and have it removed and cleaned. Depending on the model of your trailer, this wire may be a separate one. Sometimes, the ground wire is included as a part of the mounting stud.
  
  
  Trailers add the convenience of being able to carry added loads. However, malfunctioning electrical systems might often result in non-working lights, which can be dangerous and even illegal in some jurisdictions. Have your trailer wiring inspected regularly to ensure a safe and secure ride. When in doubt, refer to a mechanic for professional help.