Weeding the wiring harness (OBD1 / H.O.)

[JeepFreak21]

I'm really surprised at how little info I can find on this topic! I'm trying to reduce confusion by reducing the amount of wires in my stock wiring harness. In the sections that I have already weeded (basically from there B pillar back) I have been able to eliminate a TON of wires. Now I'm replacing my dash and gauges and I'm trying to simplify the crazy rat's nest of wires under there.

Sooooo, what can safely be cut away? More specifically, can I clip off the harness that plugs into stock gauges and indicator panel? I'm going with all custom gauges and indicators, and I think the computers have separate senders, right?

Thanks,
Billy

 

[MoparManiac]

I don't think you're going to find a step-by-step anywhere on this. Everyone has different goals on what they want to keep and how they want to do it.

I weeded my harness about 3-4 years ago when I first did the 4.0 in my MJ. All I did was take my FSM, read through the wiring diagrams, and pull pins from connectors/clip wires out until I was happy.

Be very careful reading the wiring diagrams, you really need to understand how things get fed power and where they ground. The factory liked to tap into the closest area for these so it can get fairly confusing if you aren't careful.

 

[old_man]

I have a stupid question. Why are so many people wanting to delete wires? If they are not used, then removing them has no effect. If you removed all those wires, you maybe saved 10 lbs. with absolutely no effect on performance.

 

[MoparManiac]

I have a stupid question. Why are so many people wanting to delete wires? If they are not used, then removing them has no effect. If you removed all those wires, you maybe saved 10 lbs. with absolutely no effect on performance.

Less wiring to have to deal with is about it. You mostly see this question coming from people with XJs/MJs that have been heavily modified (cages, back-halved, dove nosed, one tons, 3 links/4 links, etc.)

I removed a shitload of wiring from my '92 XJ harness I used in my MJ. Things like power windows, door locks, cruise, A/C, dome lights, overhead console, and radio wiring were all unnecessary for what I was trying to do.

Not only do you have to find a place to route that wiring after modifying the chassis for suspension upgrades, different interiors (center consoles made out of DOM, seat mounts incorporated into the body, harness mounts, etc.) you also have extra wiring as a liability. It could get corroded, ground out some where, etc.

It's really just an exercise in preventative maintenance and you get the bonus of a better understanding of what the wiring harness is comprised of.

 

[old_man]

I can understand it you are chopping things up, but its kind of like people obsessing about removing everything having to do with emissions. Anymore, the engines are designed around the emissions and removing it can actually hurt performance.

 

[MoparManiac]

That's a poor comparison. The engine is not going to stop running because you removed the power window circuit.

If you understand how the harness works you can remove/replace things you don't need.

 

[JohnnyTurbo]

I will be trimming my 91 XJ harness to remove the antilock brakes. It ran fine without the brake module plugged in.

 

[Starboard M]

I havent the foggiest if this is even close to helping, being from a Renix to HO, but I removed a TON of wires from the engine compartment and firewall.

I did the tried and true "WTF is this thing? Do I need it? No? Trace wires and cut!" method. Turned out well, the Jeep still ran, and it was amazing at how simple the harness was once I go through everything.

Most of the dash was removed as I didnt need the HVAC controls and lighting. That also helped with the engine compartment stuff, not sure if you are planning on that or not.


I did go through the harness and not just cut, but also remove the "pins" at the body harness. Currently blanking on what its call, but the big plug that goes through the firewall. If I took everything off that on the body side, I found the corresponding wire on the engine side and traced it and removed it to the source.


Looking back, I should have kept the dash shell at this point of the game, and put gauges in the stock cluster surround. It would look better, and if it was just a shell, would have weighed less than what I put in place. And would be finished.:gag:


Again, not much help since it was a renix, and a trail rig vs something Im sure you want to keep nice with the family!

Do you even wheel still?