Rear wiring harness
 

I decided to undo the years of hob job wiring in the rear end and put in a nice weather resistant junction box. Well I cut the whole harness just in front of a small chasis support as it was the closest place I could get all original wiring. There's a total of I believe 8 wires. I have 5 identified, and if memory serves me correctly, last time I was wiring this truck it had a wire dead ended from factory so that puts me at two mystery wires. Anyone have the wire functions and respective colors for these 8 wires? I've got both turn signals, reverse, ground, and marker. 1 wire is a factory option and the next two ??? Thanks for any help.

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Rear wiring harness
 

I looked at my chiltons manual this morning but that didn't do much good. I think I'm going to get some WD-40 on a rag and wire down the wires, get them nice and clean and do some color hunting. Just a shot in the dark here but I'm wodering if one of those wires is my ground for the low fuel light that doesn't work.

Rear wiring harness
 

Wipe down the wires***

Rear wiring harness
 

So these are the colors of the 8 wires...
Black/yellow
Grey
Violet/black
Grey
Brown/green
Violet/black
Grey
Green/brown

Gonna spend some time with the wiring diagrams.


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Rear wiring harness
 

And I can see some of the colors are wrong already... Sweet...


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just pulled a wiring harrness out of a parts truck it is a 93 w250 i will go check it and see what they are you dont have abs on rear of your 89 or do you, someone may have changed it at some point.

Trailer brakes ? :c:

purple- black should be brake lights +++ green with brown stripe is right turn===brown with green is left turn---black with yellow stripe is ground=== i dont have a grey but would guess they are feeds for marker lights might try this . my help . may not