Turn signal issues

[15Whitehawk]

I recently purchased a Used 2015 Jayco White Hawk Ultra Lite 20MRB from an authorized Jayco dealer (same dealer who sold it new too). They installed a 7-way connector on my old 2002 F150. Problem is, they don't know how to get the wiring correct, specifically getting the trailer turn signals working properly.

There are (2) green wires coming from the trailer into the junction box. One controls both sets of taillights and the other controls the little side orange lights on the front of the trailer. No matter how we wire it up, we can't have both the left and right turn signals working independently as both turn signal wires from the 7 way have to be wired to the lone green wire coming from the trailer.

At first we thought it was a grounding issue but I just tested with a newer F150 with the factory installed towing package and encountered the same issues when hooked up to that truck too.

Would replacing the truck flasher with an electronic or LED flasher help? At this point we're thinking my truck has an old school mechanical flasher that the trailer can't differentiate between left and right.

Thanks for any assistance/experience any of you can provide/share!

[Marcm157]

I would be a bit concerned about an RV dealer that can't isolate an electrical issue like yours. A power probe and about 30 minutes should identify the issue.

[rohuber]

Not sure why the dealer would have trouble fixing this. The left and right turn signals are on different pins on the connector.

[15Whitehawk]

The dealership never opened up the junction box on the trailer. If they had, they'd been able to figure out the issue.

I spend 9 hours fighting with the wiring today, but made progress tonight.

Had to hook the green right turn wire from the 7-way to the brown trailer wire.

The yellow left turn wire from the 7-way to the red trailer wire.

The brown wire from the 7-way ended up being the brake pedal wire, so that needed to be connected to the (2) green trailer wires.

The red wire from the 7-way is the aux power that's in sync with the cigarette lighter, so that connects to the thick black wires that connect the trailer battery to the trailer and also charges the trailer battery when live.

No wonder like colored wires connected together caused the issues!

But I don't have a wire that powers up when I turn on the headlights. There is a black wire coming from the 7-way but nothing sends power to it. For all I know at this point that black wire is the ground and the white wire is the headlamp feed. Out of daylight so I'll check that tomorrow.

[Marcm157]

Great work and yes you can rarely rely on wire color but yours seems to be worse than most! Again nice job tracing and identifying...

[15Whitehawk]

So it's only the left and right turn signal lights that slightly increase from .11 to .22 on my DC voltmeter. Shouldn't the tail/running light wire be getting current when the headlights are on? That'd be the upper right brown wire on the schematics.