Harness question.

[Rockbottom78]

Hey peeps. I'm currently pulling my lm7 5.3l out of a 2001 Silverado. I have everything disconnected and the engine and tranny are Ready to pull except one thing. The main wiring coming from the interior of the truck cab running to the underhood fuse box/computer. I'm planning on using the factory computer/wiring harness to run the engine in its new home. I may use retro fit the 01' gauges into my 78' also. I figure it may be a simple gauge upgrade as well as work well with the harness. Please let me know if I'm off my rockers. Any help is greatly appreciated. Thanks!
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[68c10airstream]

When I did my 2001 junkyard donor into my 68 c10 I found the harness splices to already show signs of corrosion. The latch tabs on most sensors and coils were brittle and broke off. I purchased at the time (6 years ago) a stand alone harness from painless wiring. Included a fuse box already populated with good relays, fuses, txh (I think) premium quality wire, and all connections had id tags. $ wire hookup, 2 grounds, 1 hot all the time, 1 hot with the key. It was $1000.00 at the time and I paid $50.00 extra for 5 additional feet of harness. I installed it inside the truck behind th
e bench seat.

Currently many vendors here offer a very good harness for less money with great reviews. I was a past ase mechanic of 30 years and don't feel like screwing around making a harness even though I specialized in drivability and electrical problem.

Cruise is very doable with cable or drive by wire throttle body.

Looks like you are a square body guy and I would think somebody by now retro fitted a newer speedo head into a stock cluster and eliminate the speedo cable.

I should add that living in the rust belt harnesses get in tough shape from the road salt eventually. Good luck and welcome aboard. This is the best truck site!!

[chuychevy82lwb]

For gauges ypu can use suburban89-91 gauges for speedo and the rest of the gauges im my honest opinion it looks better since it keeps the factory look

[Rockbottom78]

Originally Posted by chuychevy82lwb

For gauges ypu can use suburban89-91 gauges for speedo and the rest of the gauges im my honest opinion it looks better since it keeps the factory look

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[Rockbottom78]

Great info! I'm really hoping to try to use the oem harnesss and break it down myself as I'm trying to complete with really no budget to work with... But if I can't make it work I guess I'll have to cough up some doe and buy a stand alone. I want to keep the stock squarebody gauges but i assumed I could keep them with the swap. I should ad this is my first engine swap and don't have any buddies here who have done it ether. So I'm very green. But pretty mechanically inclined so I feel fairly confident.
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[Rockbottom78]

Thanks for the reply on the gauges. I'll keep that in mind as I would rather keep it more factory looking!
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[chuychevy82lwb]

I just sold the extra set of gauges i had but im sure you can find some through this forum its a great place

[69gmcc10]

I am in the same boat as you. I have a complete donor 01 and pulled the harness that runs to the fuel tank, under the dash, and the engine harness obviously. I hope to use as much of the wiring and the plugs pulled from the donor truck I can after I peel back the unnecessary things. I hope someone can answer your question...

[Rockbottom78]

Nice. Where did you cut your main wiring loom that runs into the firewall into the cab?
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[69gmcc10]

I unplugged almost everything and fed the loom through the firewall. The only wires I cut went to the stereo, heater and passenger door controls. I have allot of things to eliminate on this section of the factory harness, but the wiring and plugs for cruise, instrument cluster, obd2, and tow/haul are largely complete. I don't know if this will work but I am gonna do some research and give it a try. If all else fails I will ditch the factory under dash fuse block and go step by step through the process lined out on lt1swap.com And make a custom fuse block. Seems like an easy enough backup plan.

[Rockbottom78]

Originally Posted by 69gmcc10

I unplugged almost everything and fed the loom through the firewall. The only wires I cut went to the stereo, heater and passenger door controls. I have allot of things to eliminate on this section of the factory harness, but the wiring and plugs for cruise, instrument cluster, obd2, and tow/haul are largely complete. I don't know if this will work but I am gonna do some research and give it a try. If all else fails I will ditch the factory under dash fuse block and go step by step through the process lined out on lt1swap.com And make a custom fuse block. Seems like an easy enough backup plan.

Awesome! Thanks for the info!
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[Big Port Jimmy 6]

Lots of info here.
http://lt1swap.com/2000harness.htm

[Rockbottom78]

Originally Posted by Big Port Jimmy 6

Lots of info here.
http://lt1swap.com/2000harness.htm

Dude. That's what's up. Thank you 🙏🏼
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[Big Port Jimmy 6]

No sweat man. 30k miles on my swap and I couldn't have done it with out that info. If I had it to do again I would buy one of these.Jay
http://www.currentperformance.com/sh...erelay-module/

Originally Posted by Rockbottom78

Dude. That's what's up. Thank you ����
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[Rockbottom78]

Originally Posted by Big Port Jimmy 6

No sweat man. 30k miles on my swap and I couldn't have done it with out that info. If I had it to do again I would buy one of these.Jay
http://www.currentperformance.com/sh...erelay-module/

Oh nice. That's a decent price. Thanks again
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