Wiring a LS1
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Joined: Jun 2025
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From: Fairlawn ohio
Wiring a LS1 Hey all, new to the site. I have a 67 camaro that I am attempting an ls swap(2002 Camaro motor with 4l60e) I have everything installed. New tank, headers, oil pan, engine and trans mounts all from Holley. New radiator as well. The motor is stock low mile(30k). The wiring harness in the car is original and the harness for the motor is all there and attached still. I have gotten this far and am afraid to wire and burn the car down because due to negligence on my part. Advise I have received is to just use the stock harness vs aftermarket. Hoping there is a tutorial out there that would allow a novice like myself to follow along and get my car back on the road to enjoy with my wife and two kids(5 and 15months). Any advise to steer me in the right direction is much appreciated. I am located in Ohio 15 minutes from summit racing. I have owned this car for 17years and it has not seen the road in 6 years.thanks
Last edited by mbroa; Jun 24, 2025 at 06:37 PM.
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Joined: Sep 2008
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So I'm far from an expert but I've done a number of and helped buddies with several LS swaps. I hate wiring so I buy a aftermarket harness and stock GM ECM pre tuned for your combo.
I would replace all the stock chassis wiring harness with a new universal or custom made harness for your project. AAW and Painless get really good reviews.
Oh and maybe a typo but they didn't make a 2003 Camaro.
I would replace all the stock chassis wiring harness with a new universal or custom made harness for your project. AAW and Painless get really good reviews.
Oh and maybe a typo but they didn't make a 2003 Camaro.
In for this 2003 Camaro.. 
This is a thread I made for wiring a LS Engine in a LT1 4th Gen Fbody, since you have LS Fbody stuff the info in here will help you.
https://ls1tech.com/forums/conversio...o-lt1-car.html
This is a thread I made for wiring a LS Engine in a LT1 4th Gen Fbody, since you have LS Fbody stuff the info in here will help you.
https://ls1tech.com/forums/conversio...o-lt1-car.html
Mbroa, I did a very similar swap, review my build if you get a chance for other information that may be useful. For my wiring, I did not want to deal with the stock harness so I sold it and bought the PSI harness and used the stock computer with a tune. You sound ambitious and ready to tackle the stock harness and The Merv's link will be a great source if you continue down that path. If the stock wiring in your car is at all questionable I would consider swapping all of that out now while you can. I used American Autowire but the other companies mentioned earlier are good as well. Feel free to reach out to me with any questions that are F-body specific. Good luck with your swap and please post pictures.
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From: Ann Arbor, MI
I've had good luck on several swaps with $200 LS harnesses off ebay; always impressed by the quality of the connectors. (Maybe from the same Chinese company that makes them for GM.)
Getting the essential wiring out of a stock harness is a huge and messy job. And often too many confusing "power" wires which are connected to each other in the stock fuse block, but now have to be figured out. "The Merv" clearly knows his electrical work and can trim down a stock harness, but likely a challenge the first time.
Agree that rewiring the entire car with a new harness from any of the mentioned companies is a great idea.
Getting the essential wiring out of a stock harness is a huge and messy job. And often too many confusing "power" wires which are connected to each other in the stock fuse block, but now have to be figured out. "The Merv" clearly knows his electrical work and can trim down a stock harness, but likely a challenge the first time.
Agree that rewiring the entire car with a new harness from any of the mentioned companies is a great idea.
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Joined: Sep 2004
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From: Downers Grove, IL
If you are thinking of modifying a stock harness there is a bunch of written info and diagrams around. https://ls1tech.com/forums/conversio...schematic.html https://ls1tech.com/forums/attachmen...-02-wiring.doc
The biggest thing about wiring to understand is a wire has two ends, put them where they need to go. I've been doing it for over 20 years so it's second nature to me. Yea my first one took some time but it was my car and I learned. From there just built the knowledge and experience up. I've done a few dozen over the years, my current job is specialized electronics. My hobby of building cars helped with that, couple of Degrees in there too that needed to make it official.. 
Stripping apart a stock harness takes time, yes there's a bit there but I wouldn't scare someone out of it because it's work. I'd tell them to get in there and figure it out so they can feel accomplished after. I guess I encourage people differently. I build my own stuff, it's my work. All of it.
Once you get it all stripped down trace the wires to what is what on the PCM Connectors. Keep the essentials, take out the not needed stuff. Get it to that point lay it on the Engine and where you want to put the PCM. Mock it up where you want it. Tape up the sections of it enough to hold it together, take it out of the car then tape and loom it all back up.
Stripping apart a stock harness takes time, yes there's a bit there but I wouldn't scare someone out of it because it's work. I'd tell them to get in there and figure it out so they can feel accomplished after. I guess I encourage people differently. I build my own stuff, it's my work. All of it.
Once you get it all stripped down trace the wires to what is what on the PCM Connectors. Keep the essentials, take out the not needed stuff. Get it to that point lay it on the Engine and where you want to put the PCM. Mock it up where you want it. Tape up the sections of it enough to hold it together, take it out of the car then tape and loom it all back up.
I've had good luck on several swaps with $200 LS harnesses off ebay; always impressed by the quality of the connectors. (Maybe from the same Chinese company that makes them for GM.)
Getting the essential wiring out of a stock harness is a huge and messy job. And often too many confusing "power" wires which are connected to each other in the stock fuse block, but now have to be figured out. "The Merv" clearly knows his electrical work and can trim down a stock harness, but likely a challenge the first time.
Agree that rewiring the entire car with a new harness from any of the mentioned companies is a great idea.
Getting the essential wiring out of a stock harness is a huge and messy job. And often too many confusing "power" wires which are connected to each other in the stock fuse block, but now have to be figured out. "The Merv" clearly knows his electrical work and can trim down a stock harness, but likely a challenge the first time.
Agree that rewiring the entire car with a new harness from any of the mentioned companies is a great idea.
Did you ever finish that project where you amplified the signal of a stock front wheel ABS sensor using Dual OP Amp Preamp DC Amplification Boards with 10k resistors for traction control with Holley Dominator?
When I wired my LS1 for the first time, I got confused with their being the vehicle harness and the engine harness. I ended up hooking something with the keyed starter wiring and a wire started to get hot. Luckily I noticed I was starting to let the smoke out of the wire and got the battery disconnected. All I can really say to help is to find the PCM pinout and see what powers and grounds you need. Powers you might need to find a schematic to see if they are keyed, relay powered or straight to battery power. For keyed power, make sure with a test light that you have good power while the key is on and starting, and similar to the starting circuit, make sure there's only power there when in the start position. Make good, clean ground connections as well.