1981 J10 Trailer Wiring

[pyro]

I need to hook up a basic 4-pin trailer harness, however I'm not sure which wires (truck side) are which. Can someone point me in the right direction? thanks

[Stuka]

When I wired my old Cherokee up, I ended up doing it the hard way, which actually wasnt veryhard. Just took a multimeter and checked for voltage while I had somebody hit the brakes, and turn on the turn signals. Only took a few moments to do.

[pyro]

yea thats what i just did. now i have discovered another issue...for some reason the driver's side tail light is working only on the "low voltage" filament. the passenger side works as it should (tail on low...brake/turn on high), but i can't figure out why the driver's side is powering everything (tail/brake/turn) on the low voltage and not high at all. any ideas?

[jsinajeep]

Lot of time it not getting a good ground between the light housing and the body.

[ScottsMojo]

Right Turn Green
Left Turn Yellow
Ground White
Tail / Marker Brown
Brake Blue
Battery Red (or Black)
Back Up Purple

I believe this is industry standard.

[pyro]

yea i've got the harness wiring down pact, however it seems like every "truck side" wire is either green or white. i think i have them all correct now, i just need to figure out this bulb issue now. ill try to sand down the mounts as they seem to have been painted over.

[pyro]

i went ahead and ground down the light mounts so it is bare metal on both sides, however i am still having the same problem. where to next?

[ScottsMojo]

i went ahead and ground down the light mounts so it is bare metal on both sides, however i am still having the same problem. where to next?

Turn signal switch? Your brake/turn circuit runs through the t/s switch if memory serves me correctly.

[j20owner]

Still think you have a ground problem.

[Stuka]

Yeah it could still be a ground problem, but it could be internal to the tail light assembly, or it could even be up at the switch itself.

[pyro]

I'm going to try to source another assembly. I don't think it is the switch as the power appears to be "rerouted" to the low voltage filament. I'm not sure how to correct a ground issue other than sanding them down which I tried.

[ScottsMojo]

Do you have a wiring schematic for your truck? You have two circuits to your tail lights - marker circuit and stop/turn circuit. And of course, ground. I would do a little troubleshooting and from either end, at each point of connection apply 12v power and ground to each of the circuits. Keep working towards the other end until you find your lack of continuity or short, whichever might be the case.

It might take a little time, but you will logically work through the circuits and find the problem without throwing parts at it. Then the repair becomes crystal clear.

[pyro]

anyone try one of these before?
http://pages.ebay.com/link/?nav=item.vi ... 1152419360

[ScottsMojo]

anyone try one of these before?
http://pages.ebay.com/link/?nav=item.vi ... 1152419360

Didn't even think of that! I changed bulbs some months ago and the springs were shot. Is that your problem? Lack of contact in the socket?