Rebuilding a wiring harness

[JCampbell]

Anybody ever rebuild a wiring harness for a TBI truck?

Picked up a '90 Suburban with a TBI 454/TH400 with the intent of using the engine and trans in my '77. I was planning on swapping the entire wiring harness over as well.

The factory harness from the firewall port under the brake booster and the portion for the TBI from the computer forward is pretty thrashed. I'm actually surprised this truck even ran. I haven't began testing for continuity, but that aside, most of the plastic connectors are broken or otherwise damaged.

Has anyone rebuilt a factory harness? Where did you source the connectors, etc? Is there anyone out there that makes a replacement harness for this truck?

[D.FENS]

Howell has the engine side pretty well covered

http://howellefi.com/gm-tbi-products...sses-only.html

Painless makes a replacement body harness, but they definitely don't give them away.

Weather-Pak plug bodies and terminals can be sourced through Summit. Car Quest or AC / Delco stores may be able to order them if you want to stay local. Some of the TBi specific stuff may have to be ordered from the dealer.

[Greenlee]

I am using the entire harness and fuse block from an 89' Suburban. I am not totally done yet, but I do have it running. Getting it out of the Suburban without tearing it up or breaking any connectors was the most frustrating part. Once I got it out it was pretty easy. I just had to repair a few wires and cover everything with new loom. Putting it back together in the new truck is just plug and play. From what i have read, I actually think this may be easier than the painless systems because they are not cut to length and don't come with connectors.
Posted via Mobile Device

[Gordonr1973]

Originally Posted by Greenlee

I am using the entire harness and fuse block from an 89' Suburban. I am not totally done yet, but I do have it running. Getting it out of the Suburban without tearing it up or breaking any connectors was the most frustrating part. Once I got it out it was pretty easy. I just had to repair a few wires and cover everything with new loom. Putting it back together in the new truck is just plug and play. From what i have read, I actually think this may be easier than the painless systems because they are not cut to length and don't come with connectors.
Posted via Mobile Device

It would be easier to go this route.

The Painless wiring harness is simply a chassis harness. Not a Chevy Chassis harness either, but a generic harness that they slap a sticker on the box stating the years & make of vehicle you ordered it for so you think you are getting a 'custom' harness.

I had a ton of trouble installing mine because I had to locate and use the old connectors from my old harness onto the new Painless harness, plus the amount of excess wire they supply makes it even more confusing --- remember, Painless harness might cover a short box to an extended cab long box to a RV...they don't discriminate between anything.

There are little differences as well that I am discovering as my build gets more complete: this week's discovery was that with the Painless harness, the power window switches are always 'live' unlike the GM original harness where they are on a pink (Iginition/accessory) only circuit.

I will never again use a Pailess product in any project of mine.

I heard another comany, I think it is called American Auto Wire, has a complete with connectors wiring harness specific to the vehicle. May be a better route to go than Painless.

[JCampbell]

As long as I can get the weatherpacks, I think I can rebuild the one I have. It's just going to take a few hours of uninterrupted time and a wiring diagram.

Speaking of which, anybody know where I can get a pinout/wiring diagram?

[D.FENS]

Originally Posted by Gordonr1973

It would be easier to go this route.

The Painless wiring harness is simply a chassis harness. Not a Chevy Chassis harness either, but a generic harness that they slap a sticker on the box stating the years & make of vehicle you ordered it for so you think you are getting a 'custom' harness.

I had a ton of trouble installing mine because I had to locate and use the old connectors from my old harness onto the new Painless harness, plus the amount of excess wire they supply makes it even more confusing --- remember, Painless harness might cover a short box to an extended cab long box to a RV...they don't discriminate between anything.

There are little differences as well that I am discovering as my build gets more complete: this week's discovery was that with the Painless harness, the power window switches are always 'live' unlike the GM original harness where they are on a pink (Iginition/accessory) only circuit.

I will never again use a Pailess product in any project of mine.

I heard another comany, I think it is called American Auto Wire, has a complete with connectors wiring harness specific to the vehicle. May be a better route to go than Painless.

Summit lists it as a squarebody-specific harness. I've never bought one, so I can't say. Don't take this as me trying to argue on the internet, because we all know where that goes. I'm just sayin.

http://www.summitracing.com/parts/PRF-10205/

Originally Posted by JCampbell

As long as I can get the weatherpacks, I think I can rebuild the one I have. It's just going to take a few hours of uninterrupted time and a wiring diagram.

Speaking of which, anybody know where I can get a pinout/wiring diagram?

I bought a used dealership wiring harness manual (in a 3-ring binder) on eBay. Think it was $20 shipped.

[Gordonr1973]

[QUOTE=D.FENS;5439279]Summit lists it as a squarebody-specific harness. I've never bought one, so I can't say. Don't take this as me trying to argue on the internet, because we all know where that goes. I'm just sayin.

http://www.summitracing.com/parts/PRF-10205/


I bought that exact one from Summit and what I said was just my experience with it compared to other harnesses I've used in the past.

Just because it has a sticker on the box that says it can be used on a square doesn't mean it can 't have another sticker slapped on it saying it is specific for a Chevelle, Camaro, or even a Ford.

That's the problem I have with Painless: it is being marketed as a specific harness and it is not.

If it were indeed a specific harness it would have the connectors on it instead of reusing connectors from your old harness.

If anyone reading this in the future is deciding whether to buy that harness or not will see for themselves if they go the Painless route. And I'm not into arguing either so that's about all I have to say about the subject :-)

[Gordonr1973]

Originally Posted by JCampbell

As long as I can get the weatherpacks, I think I can rebuild the one I have. It's just going to take a few hours of uninterrupted time and a wiring diagram.

Speaking of which, anybody know where I can get a pinout/wiring diagram?

I can't think of the fellow's avatar & screen name, but if you search the site there is a guy who posted all the wiring diagrams. Maybe check out Jeff Drew's site: www.73-87.com

I think he had some diagrams there as well.

[SCOTI]

Originally Posted by JCampbell

As long as I can get the weatherpacks, I think I can rebuild the one I have. It's just going to take a few hours of uninterrupted time and a wiring diagram.

Speaking of which, anybody know where I can get a pinout/wiring diagram?

The wiring diagrams/manual will only get you so far. Get a service manual to use in conjunction w/the wiring manual & you'll limit the headaches. I've been sorting through the TBI wiring for my 89 dually. I'm amazed it ran as well as it did (before the sudden death) w/all the broken & exposed wiring under the hood. My tech info came from dealership tech groups via board-members (Jonboy got me the wiring manual & MattA got me an old service manual).

I've been sorting through as many fudged wires as possible & splicing in fresh where required (& eliminating other wiring).

[JCampbell]

I’m just going to have to clear off my work table and set aside some time to dive into it. Now that I have it out of the truck and I’ve looked it over, I don’t think it’ll be that bad.

I think solder and heatshrink will be my new best friends though.