REAL MAN TRUCKWORKS & SURVIVAL

VEHICLES, CAMPERS, and BOATS => Everything Trailer, Camper, or RV related => Topic started by: EL TATE on May 18, 2015, 12:03:44 PM

Title: 7 pin wiring issues
Post by: EL TATE on May 18, 2015, 12:03:44 PM
On my '03 LB7 I have a wiring problem. running lights, check. Left and right turn signals, check. RR brake light check. LR brake light?  I have power from the yellow wire when the blinker is flashing, but not when the brakes are applied. what gives? Any ideas or experiences with this?
Title: Re: 7 pin wiring issues
Post by: Nate on May 18, 2015, 12:12:03 PM
Is the lens chipped at all?  Did you check to see if there is corossion in the bulb socket?   My lens had a small chip in it and over time the bulb socket got corroded.
Title: Re: 7 pin wiring issues
Post by: EL TATE on May 18, 2015, 01:16:18 PM
bulb socket is good. hooked up another rig and confirmed the issue lies w/ the new truck. swapped bulbs to be sure and consistent left side only issues. blinker fires, runners light, but brakes only on passenger side. ran a lead tester on the driver's side terminal at the connector on the bumper and came up w/ the same. power with blinker but no brakes on left side only. I should also point out that it's the only wire out of the loom and spliced to other smaller blue wires.
Title: Re: 7 pin wiring issues
Post by: KensAuto on May 18, 2015, 01:17:25 PM
RV plug? I believe there's a separate trailer brake light fuse in the underhood fuse panel.
Title: Re: 7 pin wiring issues
Post by: KensAuto on May 18, 2015, 01:30:46 PM
Scratch that...just looked at an 03 wiring schematic. The left and rt turn (yellow and green) come straight from the flasher module. There might be a reason they tied into that wire. You might try cutting those blue ones.
Title: Re: 7 pin wiring issues
Post by: EL TATE on May 18, 2015, 01:36:44 PM
Scratch that...just looked at an 03 wiring schematic. The left and rt turn (yellow and green) come straight from the flasher module. There might be a reason they tied into that wire. You might try cutting those blue ones.

I thought of that, but had to drive the truck into work today and it was already 9:30pm. didn't want to be without signals for the 40 mile commute if something didn't work out right. I'm taking a look at things again at the shop here at lunch. the funny thing is there are two, smaller blue wires from two separate looms tied into one spade fitting on the yellow wire of the trailer harness. no idea why they did this. it's heat shrunk and insulated well, so it looks to be professional, but no explanation for sure.
Title: Re: 7 pin wiring issues
Post by: Sammconn on May 18, 2015, 01:38:26 PM
Not sure if the 03 is the same as the 06. I've had fuses blow, they are marked as trl rt, etc. Other than that it sounds like there may be some suspect wiring in there too.
Title: Re: 7 pin wiring issues
Post by: KensAuto on May 18, 2015, 01:49:21 PM
If I had to guess, I would say they might have had issues with the truck turn light housing, and I bet those wires run up to it.
Title: Re: 7 pin wiring issues
Post by: EL TATE on May 18, 2015, 04:36:47 PM
If I had to guess, I would say they might have had issues with the truck turn light housing, and I bet those wires run up to it.

It had a 5th wheel in a previous life and was hooked up with an additional wiring harness that was NLA. Got the right plug in the right terminal and voila.
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