Adding a 4 way trailer plug to the rear

[wetzk]

We decided to add a plug to the rear to power the license plate light when the tag is moved to the bike rack. The lower lights are easily visible through the spokes and it also has the top ones so we did not need to add brake or stop lights. The license plate is the only item that is obscured by the bicycles, and if we drive at night it needed a light so.....

Make sure you verify before you wire in the harness.
There was a flat 4 wire trailer cable running along the back.
I thought nice, this should be easy. Nope

On ours, the white did nothing, brown was right turn, green was tail/running and yellow did nothing. The left turn wiring was connected to a red lead over to the side of the lights.
I cut the tie wraps so I could look at what was there and found another white wire that was being used for ground.

End result, we now have a functional light on the bike rack and if we ever decide to use a bicycle cover it would not be hard to add the lights to the rack for stop/turn/tail.

 

[rubicon327]

Glad you got it figured out. Had a similar issue with a flat 4 plug wired wrong from the factory. This might explain all or part of your issue:

http://www.escapeforum.org/forums/f8/adding-after-market-front-storage-box-4007-6.html#post145608

 

[wetzk]

Glad you got it figured out. Had a similar issue with a flat 4 plug wired wrong from the factory. This might explain all or part of your issue:

http://www.escapeforum.org/forums/f8/adding-after-market-front-storage-box-4007-6.html#post145608

I was planning to check since their are 2 ways used for the parking and right turn/stop wiring.
What threw me was no ground or left turn/stop. So I had to tear the wiring all apart before I could figure which wire did what.
I can see why they did not use the yellow, they just used a red wire right at the left side which did seem odd but I should not need to mess with it again. But the ground, why run a separate one? I guess they did not feel like separating the 4 wires.

 

[rubicon327]

I was planning to check since their are 2 ways used for the parking and right turn/stop wiring.
What threw me was no ground or left turn/stop. So I had to tear the wiring all apart before I could figure which wire did what.
I can see why they did not use the yellow, they just used a red wire right at the left side which did seem odd but I should not need to mess with it again. But the ground, why run a separate one? I guess they did not feel like separating the 4 wires.

Ok your colors and functions match what is expected at the 7 pin and carried back through the trailer. Yellow is unused because it is for reverse lights. Not sure why they did the grounds that way. I guess my linked post is really only helpful if you are wiring in a flat 4 plug with full functionality.

 

[wetzk]

Ok your colors and functions match what is expected at the 7 pin and carried back through the trailer. Yellow is unused because it is for reverse lights. Not sure why they did the grounds that way. I guess my linked post is really only helpful if you are wiring in a flat 4 plug with full functionality.

RV's would have to be different.
I'm used to bucket trucks. pole haulers and generator/equipment trailers as far as checking wiring.
I did not realize there are three not two wiring standards.
I was going with traditional not rv. We used it and commercial.
I never have had to mess with the wiring on anything I owned other than boats and they use the 4 pole wiring. You threw me with the left being red and yellow being reverse so I had to go look.
Now it makes sense.

 

[Brian B-P]

The arrangement labelled as "traditional" in that illustration from Hopkins isn't traditional at all - it is the SAE standard used for commercial vehicles with the round-pin connector, but applied to the flat-pin connector. The "RV" standard is the arrangement used for decades with these connectors; it is what should be expected with this connector, but anyone can use any colour they want, so assume nothing.