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92 front harness meets 86 rear, Haynes diagrams are near useless

BenWheelin

NAXJA Forum User
Location
Texas
Hello all,

I've built my 86 two door into a 92 from the dash forward. I'm now splicing the late dash harness to the early body harness and have nothing more than a Haynes manual for diagrams. So far, I have the exterior lights working, but nothing matches the book. I accomplished that with a test light.

My primary issue is the rear wiper and defrost. I know the 86 functioned as intended. The 92 came with a different hatch, not quite right, that was a bird's nest of wiring that didn't quite match. The lock motor and tag light worked, but nothing else.

I could get into the hatch, but it has to be unlocked first. The cylinder is toast, and while I have power to the driver's door, I'm not actuating any relays. If one could suggest where to jump just to unlock once, it would help. I'm getting power from the lock switch both ways at the door connector, but not a sound.

Interestingly enough, the connector at the fuel sending unit is identical, with a plug in the pigtail which would feed an electric fuel pump. It'll be easy enough to identify the leads inside with a multi meter, but that's only two wires with more than one whole connector to go.

I can trace a good bit on the donor, but I know the hatch wiring was never right. Any help is greatly appreciated.
 
The wiper runs and parks so long as the key remains on, runs with the wash. Fuel pump circuit is in and the late gauge is reading a near empty tank on the early sending unit. I could use the color code for the seatbelt warning lamp, hatch speaker color code and their respective sides, early and late, and a diagram of the early heated rear window.
 
It runs. Still no power windows or locks, no seatbelt warning light. No parking brake warning light. I feel both of those circuits are going to switch to ground.

Brake circuit should be the same color as the one on the proportioning valve, no?

Seatbelt circuit is white, but white on the dash side is the wash circuit for the rear window. I'm not really that excited about grounding hot circuits to see if the dash lights up.
 
If your going to ground unknown wires do it with an inline fuse holder between the wire and ground

Just buy a lot of fuses

Yeah, I have a pretty large assortment of fuses in a box dedicated solely for electrical work. An inline holder is as simple as two female spade terminals, insulated with shrink tubing if I should leave it there. I have smaller spades that fit mini fuses and relays as well. Fun stuff.

The seatbelt warning lamp is on a timer so the circuit should be hot for a moment with the key on, then off, but I haven't observed anything as such at the dash side. The seatbelt connection at the floor is white, and shows continuity to the white wire at the body harness connection. When I get back to it, I intend to dig out the wire on the parking brake lever, then compare to the color code under the hood at the proportioning valve, and find both at the body harness connectors. Once I understand how the circuit is wired, then I test it with jumpers.

I expect unused circuits due to a disparity in numbers between early and late. My body harness lacks the late model power mirror control, two back doors, overhead console, and possibly other things I'm not considering at present.

Still haven't checked for power at the seat connections. There's a lot to learn and understand in there.
 
i would be looking for factory service manuals, i have one for my 94, wouldn't give it up.

I need a few of them for different years, honestly. I think I'd be good with 88, 90, 91 or 92, and 96. Things I really should own already, but that shouldn't get in the way of progress.

Can you tell me what the respective speaker color codes are for the rear? I'm not installing speakers, but I can at least have them wired so they aren't just hanging there. Not asking for a picture, your personal interpretation is adequate for me.
 
Need more info on the 2 jeeps -- motor,trans, trim level, 2wd - 4wd?

The one I'm building is (was) a 1986 Laredo two door 2.8/AX5/207 but is now a 92 Laredo from the dash forward. It now sports a 4.0/AW4/231. The 92 is a four door. I'm using the late model bulkhead connector/fuse panel and cutting off the late model connectors as I solder each circuit into the early dash side body connector.

Took a lot of metal work to get it where it is.
 
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It came with a fuel pump circuit, I suppose for the 2.5 TBI, and while the 2.8 model lacks a fuel filter at the frame because its in the fuel inlet of the carburetor, the holes were there and the bolts are self tapping to mount a hanger where it goes on the frame. Fuel tank internals are totally different but the late model sending unit plugs in. Nothing exists to support it in the bottom of the tank, so it will have to be replaced as well. Conversely, the late model tank does not accept the early pickup tube because of said support.

It really has been a fun project, and should prove a fun truck in the end.
 
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Got the brake warning light wired, found it by accident with the test light. It illuminated dimly and I noticed it correlated with a dim brake warning light. Not even the same colors as under the hood. Got power windows and locks, part of the early door harness carries the ground circuit in between the speaker connections in a separate plug. Grounded that, got windows and locks. For test purposes, I had the window circuit tied into the hazard lamp slot through a jumper so I wouldn't have to leave the key on, now I can open the hatch!

Still not sure about the seatbelt warning lamp, or the speaker wiring, but at least that should come to light behind the hatch trim. I have power at the seat connector for power seats.
 
Speaker wiring is tied in, everything works but the seatbelt warning light. I have a few wires I can't find a use for, one being the hatch dome circuit. It's yellow at the late dash harness, won't be hard to figure that one out.

There's a green wire I don't understand remaining, and a pink wire that's always hot.

There's a pink wire on the body side I haven't found anywhere else.
 
Thanks for the tip, I hadn't checked the vanity mirrors yet. The Dome connection was on the passenger side and it plugged right in, as did the keyless entry control. Wish I had a fob for it.

They yellow I think feeds the power mirror setup in the 92, as I found one on the switch under the console.

The gray wire from the hatch dome switch is black/white at the body connector up front. I was unable to get it to ground properly, and I tend to leave the hatch open enough to drain the battery, so I opted to leave it disconnected.

The only wires left are a green/black on the body side and a green on the dash side. The body side pink wire could explain why the rear dome doesn't come on. Besides that and the seatbelt warning light, everything works fine from what I can tell.
 
yellow is either switchd ground or switch pos for dome lights. you'll find a black and yellow pigtail for the dome light switches in the left and right kickpanels, left is a three pin, right is two.
 
I feel like it's the ground side of the dome light, which is why I was surprised to see it at the mirror control. Hit it with a test light, and it actuates the dome light timer, but it goes out in forty five seconds or so. I could have connected the hatch switch lead to it, but I couldn't get it to ground consistently.

Otherwise, I'm going to have to murder the door jamb from the looks of it. The 86 has two leads from the door switch, and the hole is smaller. Looks to be formed into a collar which is then threaded. I'll have to open it up with a rasp or something and just run the late model in. Think I can get away with the original on the passenger side, just clip and solder the late model connector on.

Had to run out in the cold last night to find out, there's no power to the vanity mirror. Pretty sure it worked previously.
 
It already had the sentinel system, or headlight timer, which I found useful enough, but I think having the late model's timer delayed dome lamp system will be quite cool in the 86.

Honestly, I take great amusement in the fact that it's all original, only it didn't come with any of it. Highly modified to factory spec.

Merry Christmas, y'all.
 
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