What Gauge Wire Is Needed To Be Ran From A Brake Controller To My 1993 GMC C/K Series Pickup

Question:

Hi I have a 1993 GMC Sierra K3500 and I am redoing the wiring to a 7 pole connector at the back hitch and adding another 7 pole connector in the bed for my fifth wheel. 2 Questions: 1 What gauge wire should I run from the brake controller blue wire and the hot power lead from the battery to both 7 pole connectors? I have a 2011 Forest River 37foot Toy Hauler with two axles. 13,500 pounds maximum. 2 My truck has the factory 4 wire harness on the frame by the back bumper and since I want to split all the wires to two connectors, can I use a a 7 pole weatherproof trailer wiring harness junction box like etrailer # e99011 that is actually meant to be on the trailer? I could replace the plug with one of the connectors and wire my second 7 pole connector to the same box. I know I still have to bring the blue brake wire and the hot power lead back to this junction box.

asked by: Bill H

Expert Reply:

The black and blue wiring that comes from the brake controller is 12 gauge so you will need butt connector # DW05745-5 to hook them correctly to the vehicle, and for the red and white wire they're both 16 gauge wire so you will need butt connector # DW05744-5.

To make your 4 flat wire harness on your 1993 GMC C/K Series Pickup you would need wiring # ETBC7. This will adapt your 4 flat into a 7 round plug and four flat, which will provide the wires necessary to hook up to your controller stated above.

You can use the junction box # HS381-9000 to split your harnesses to be able to run to 7 round plugs. You would also need wiring adapter # 50-87-007.