Both Trailer Turn Signals Flash When Tow Vehicle Headlights are On
Question:
Hello I just wired my trailer and already replaced the 4 prong connector on my truck. With the truck on the blinkers work fine and only the correct light comes on with each blinker. When I turn the truck lights on and then turn my blinker on either one both lights on the trailer blink back and forth. Truck harness is hooked up yellow to yellow, brown to brown, and green to green with white grounded to frame. And trailers lot is new with grounded bolts built into the lights. I am wondering why my lights both blink when truck nights are on. Also there is a teal blue/green wire that I originally had connected to white wire on the truck side.
asked by: Spencer R
Expert Reply:
What you describe is a classic symptom of a poor ground connection. Everything works okay until you turn on the vehicle's headlights or running lights, then things get interesting. When the headlights are on, the wiring for the lighting on the trailer is under full load which is when a problem will show itself.
The trailer connector ground should be securely attached to the trailer tongue, to clean bare metal. Remove the ground screw or bolt and sand down a dime-sized area around the hole where the ground attaches down to bare metal. Reattach the ground screw or bolt using a star washer between the ring terminal and the metal of the trailer. The star washer will ensure that you get a good bite into the metal of the trailer tongue for a reliable connection. Once the ground screw or bolt is ran down, use give the ground connection a good shot of rust inhibiting spray paint to protect it. Also, make sure the trailer connector on the vehicle is grounded as described above.
Next, check the ground connection on each of the lamps. If the lamp has a dedicated ground wire, be sure its securely attached to the trailer frame. If it's the type of lamp that grounds through its mounting hardware, be sure that the lamp is connected either directly to metal that's in contact with the trailer or run a jumper from the attachment point to the trailer frame.
I've linked you to our trailer wiring troubleshooting article, I hope you'll find it helpful.
Product Page this Question was Asked From
Combination LED Trailer Tail Light - Submersible - 6 Function - 11 Diodes - Passenger Side
- Trailer Lights
- Tail Lights
- Rear Reflector
- Side Marker
- Side Reflector
- Stop/Turn/Tail
- Square
- Surface Mount
- Submersible Lights
- LED Light
- 5L x 5W Inch
- Red
- Optronics
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