Looking for a complete powertrain wiring harness.

Fireball5657

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Hey all, I have a 1994 GMC K1500 with the TBI 350 and a 4L60E. I’ve been having wiring issues with the transmission harness since the metal holder for the harness at the bell housing has rubbed through the wire loom and is starting to rub through the wires themselves. I’ve patched the spots where the wires were broke for now, but eventually I would like to look into a whole new powertrain harness to avoid any electrical headaches down the line. There doesn’t seem to be much on the forums about getting a new harness for the later TBIs, but I was hoping someone might have some insight into what the best course of action is. I’m not against the idea of building my own harness, but it would have to be entirely new connectors, wires, everything, and that sounds like a big task. And I’m not sure the best place to go to buy the new connectors or the color coded wires. Could any of you wiring wizards help me out with this?
 

someotherguy

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New harnesses don't exist, for the most part. You might luck out and find some old stock sitting on someone's shelf, but trust me, most dealers are getting rid of stuff the moment they can justify making room for newer parts - and for a 1994 model, that was almost 20 years ago. Buying all the connectors, if you can find them, would be mind-blowingly cost-prohibitive.. ever look at the prices for the common pigtails that are readily available for these trucks?

Best bet is a boneyard harness from a truck that hasn't been butchered. For your purposes, a similar model 1993-1994 only, will be the donor. 1994 is the best bet as you won't have to make any modifications. 1993 is similar but lacking a few minor items (like for example the purge solenoid on the EVAP.) Obviously it should be a K1500 or a light duty K2500 (6 lug, not 8 lug) so you get the 4L60E connector and single speed sensor setup, as opposed to an 8 lug K2500 which will be 4L80E, dual speed sensors.

Richard
 

Fireball5657

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New harnesses don't exist, for the most part. You might luck out and find some old stock sitting on someone's shelf, but trust me, most dealers are getting rid of stuff the moment they can justify making room for newer parts - and for a 1994 model, that was almost 20 years ago. Buying all the connectors, if you can find them, would be mind-blowingly cost-prohibitive.. ever look at the prices for the common pigtails that are readily available for these trucks?

Best bet is a boneyard harness from a truck that hasn't been butchered. For your purposes, a similar model 1993-1994 only, will be the donor. 1994 is the best bet as you won't have to make any modifications. 1993 is similar but lacking a few minor items (like for example the purge solenoid on the EVAP.) Obviously it should be a K1500 or a light duty K2500 (6 lug, not 8 lug) so you get the 4L60E connector and single speed sensor setup, as opposed to an 8 lug K2500 which will be 4L80E, dual speed sensors.

Richard
Yeah, I was afraid of that. The thing is that there’s nothing really wrong with the current harness, everything works fine now that I’ve fixed the transmission stuff, but all the clips on the sensors are broken and some of the wires like the CTS on the head and the knock sensor have exposed copper; everything works, but for me a new harness is just a piece of mind thing. If I go and pull a harness out of another truck, it’s still going to have 30 year old wires and connectors, and that’s not really an improvement over what’s in the truck right now. I may just have to build my own harness over the next year or so and then just swap it out when I’m done. I know the connectors are expensive, I’ve been looking at doing this for a while now, but I really don’t want to deal with the headache of having wiring issues down the line. And if those $40 a piece connectors last another 30 years I’d be okay with it. I’ll keep looking for other options, but I may have to build one myself. Thanks for the insight.


Also, if anyone knows the part number for the 94’ 350 K1500 harness that would be awesome. If I can’t find one (and I probably won’t), then maybe I could find pictures and build my harness from that.
 

xXxPARAGONxXx

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If the main issue is the connectors (i.e., the clips on the connectors), you can de-pin those broken connectors and re-install the pins into a new connector. GM/ACDelco still sells most of the connectors, and if not, as a last resort, you can source a used (but not broken) connector at a junkyard.

To determine the P/N of your engine harness, you can PM me your VIN. If you are savvy enough at using GM Parts Giant, you can input your VIN there and find your engine harness P/N.

Building an an engine or dash harness from scratch is a pretty monumental task.
 
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