Here is the mystery plug I cant figure out what it is. I thought it was a factory tach wire, but I dont think Im correct on that one.



Kasey

 

One more shot.


Kasey

 

I am not sure what that is I know it is not the tach wire though.

 

Is it the rear load sensing ABS plug?
This truck had that, and I got rid of it becaust it was SHOT, and I wasnt gonna spend $250 bucks to replace it.

Kasey

 

Where's it located?

If it's under the dash it could be for Cargo light or Overdrive Switch (if it doesn't have either one)

 

There is no tach plug on a '91. Like Brandon said, maybe cargo lamp?

 

The orange wire makes me think it's something to do with a light, usually the orange wire is the Domelight/cargo light system

 

The truck has both a cargo liget, and 4 speed overdrive. Im still Confused myself.

Kasey

 

Parking brake warning light wire?

 

Where is it located?

Looks like the second plugin for the engine harness.

 

It was tapped to the top side of the large fuse pannel harness. There is another plug thats retained by a push pinn under the dash thats square, I think thats the engine harness.

Kasey

 

I looked in my truck and I have that same plug tapped to the harness right over the hood release handle. Mine is not hooked up to anything either and I think I have every electrical option that was available. Maybe it was for something when it was built?

 

I looked all through the manual for both the non-intercooled and intercooled trucks and couldn't find any plugs that looked like that. I know that my truck has that plug too and I never knew what it went to. I appears to plug into a printed circuit board, like the one on the back of the gauge cluster. The only thing I can think of that it could be for is something to do with the rear hatch on a Ramcharger, but I don't know if they used the same wiring harness on those as they did on the trucks.

 

Mine also has basically every option except power seats, and I dont even know if that was an option.

The ramcharger rear hatch thing might be it.

I also looked through my service manual, and found zilch. Mine is a 92 manual though.

Kasey

 

It's NOT RamCharger related, as the dash harness in a Diesel truck is wired totally different for the Message Center, among other things.
The pick-ups also do not have the wiring for the heated backglass, plus the wiring for that is a much heavier guage.

The squarish 2-pinned plug, that's push-pinned to the hood release cable, is a diagnostic plug for the ABS.

This unknown plug is on 1988-'91, even intercooled, but not on 1992-'93.
Even a '92 gasser truck doesn't have it, but a '91 gasser does.

I'm leaning towards an accessory plug, but it's possible it is also a diagnostic plug.

Mark.