Trailer Junction Box Installation on Trailer to Avoid Use of Wiring Adapters

Question:

Hi, I have a 2018 Jeep gc. I bought a 7pole adapter to 7 pin and 4 pin. When I put a tester in all lights light up and blink with hazards. When I attach my trailer via 4 pin all lights work expect left blinker does not flash. When I use another vehicle it works perfectly. I tested the adapter on my vehicle and it look like all system go so I am very flustered. Only other thing I can think of is the fuses but it’s a brand new vehicle? Unless Jeep makes you buy factory parts only and all others don’t work correctly?

asked by: Jeeemy

Expert Reply:

Sometimes trailer wiring adapters do cause odd behavior from vehicle lights, trailer lights or both. It is often better to do an actual re-wiring of the trailer to match the vehicle's connector so that adapter complications are avoided. Fewer connections are also generally more reliable.

A 7-way junction box like # HS381-9000 mounts to your trailer frame and it comes with a 7 way cord. Simply cut off the existing trailer 4-pole connector and apply ring terminals like # 44-5310A to the trailer's existing wires so you can connect them inside the junction box.

The linked article shows you how the 7-way should be configured.

expert reply by: Adam R