Do I Need To Ground the Trailer Junction Box If Running a Ground Wire For Each Light To This

Updated 09/05/2019 | Published 09/04/2019

Products Featured in This Question

Wiring Kit for Hydrastar Electric Over Hydraulic Actuators

(12)

$83.69

12 Gauge Wire - Black Primary - Per Foot

(30)

$1.53

16-Gauge Bonded 3 Wire - per foot

(43)

$1.34

Question:

I’m redoing all the wiring on my 18ft car trailer . has a lot of rust on underside so finding a good ground is not going to be easy. so I seen some manufactures that ground every light on trailer to the ground of the 7 way.then grounds to the tow vehicle.is there a diagram I could use if I was to do this.do I still run a ground from the junction box to trailers tongue or only ground is the tow vehicle.right now every light on trailer has its own ground and if possible I’d like to eliminate that and make sure I have a good ground source for every light . All lights are led currently. Allso is it possible to wire the marker lights on sides to be turn signals.

asked by: Casey

Expert Reply:

If you will be running a ground jumper wire for each light on the trailer up to the junction box then you would need to also ground this bundle of wires from the junction box to the main trailer ground which is usually on or near the coupler. The ground for the tow vehicle's trailer connector would not support all of the trailer lights and trailer side connector. I don't have any diagrams of this setup unfortunately.

In order to redo your wring I recommend using the Trailer Wiring 7-Way Upgrade Kit part # HS381-9000, with the 16-Gauge Bonded 3 Wire part # 16-3B-1 (per foot) for the signal lights, and then the 12 Gauge Black Primary Wire part # 12-1-1 (per foot) for the grounds.

It is possible to tie the side marker lights into the turn signal circuit, just splice into the green/yellow wire above.

expert reply by: Conner L