Thinking about re wiring Who makes the best harness - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**1970 CST Short Wide** · 09-12-2024, 10:01 PM

What are guys using as far as re wiring harness kits. I’ve heard of American Wire and Painless. Are there any more out there. Would like to hear suggestions

Thanks

**mongocanfly** · 09-12-2024, 10:05 PM

I used American Autowire..and will use them in the future ..very nice kit
Have a buddy that's used kwikwire on several of his..

**A1971Blazer** · 09-13-2024, 07:41 AM

I used the M&H upgrade kit on my '67 with great success.

**Sheepdip** · 09-13-2024, 10:31 AM

My boy used Painless and it was straight forward and pretty simple or at least I thought so.

**1970 CST Short Wide** · 09-13-2024, 11:00 AM

Quote:

Originally Posted by A1971Blazer

I used the M&H upgrade kit on my '67 with great success.

I would like to know more about this one. What does a Upgrade Kit include
Who is M&H - Web Site ?

**kwmech** · 09-13-2024, 11:17 AM

I've used a Painless kit before and it was anything but, plus a lot of undersized wires. American Auto Wire has been my go to for the past 3 kits

**Boog** · 09-13-2024, 11:28 AM

Aaw.

**biketopia** · 09-13-2024, 11:45 AM

I have an AAW for my project. My brother installed one of there kits in his 70 Camaro and prefered it over the previous Painless kits he's used. Some of the "update" stuff is modern blade type fuses and relays for headlights.

https://67-72chevytrucks.com/vboard/...d.php?t=642579

LS short box · 09-13-2024, 04:19 PM

I used Painless on my hot rods that needed a total rewire. They worked well. I used the 21 universal kit. Not the direct fit kits.

**HO455** · 09-13-2024, 07:00 PM

Are you doing a plug and play stock replacement or do you have major changes in mind?

**1970 CST Short Wide** · 09-14-2024, 01:07 AM

My Big ? Is I have Dakota Digital, Vantage Air, A1 Power windows, LS1 Computer which all have there own harness. So what am I really Re Wiring

**old Rusty C10** · 09-14-2024, 09:37 AM

i built a custom truck using a squarebody drivetrain with a 51 international as the body. I used American Auto Wire and the harness is great and easy to install

**A1971Blazer** · 09-14-2024, 10:00 AM

Quote:

Originally Posted by 1970 CST Short Wide

I would like to know more about this one. What does a Upgrade Kit include
Who is M&H - Web Site ?

Here's a link to the website. https://www.wiringharness.com/
The upgrade has the ATO blade type fuses, it also includes several extra high amp fused circuits and an additional heavy gage feed wire into the fuse block to feed the additional circuits.

LS short box · 09-14-2024, 04:33 PM

The LS ECM will need 12 volts constant and 12 volts in start and run when you turn the key. Your LS harness should include a fan relay and fuel pump relay.
I assume you will need a relay for the power windows.
Same with the AC circuit.
Gauges I'm thinking 12 volts in key on and run. Check with Dakota if it needs a constant 12 volt.
You have so much aftermarket stuff a direct fit harness would be a waste of money if its a lot more money than a universal kit IMO.
I love to hide wires. So on my 68 project I moved the Painless fuse block away from the fire wall and welded the hole shut. Then made a small hole and ran the chassis wires forward and back along the frame rail.
See pics.

**1970 CST Short Wide** · 09-14-2024, 11:51 PM

Quote:

Originally Posted by LS short box

The LS ECM will need 12 volts constant and 12 volts in start and run when you turn the key. Your LS harness should include a fan relay and fuel pump relay.
I assume you will need a relay for the power windows.
Same with the AC circuit.
Gauges I'm thinking 12 volts in key on and run. Check with Dakota if it needs a constant 12 volt.
You have so much aftermarket stuff a direct fit harness would be a waste of money if its a lot more money than a universal kit IMO.
I love to hide wires. So on my 68 project I moved the Painless fuse block away from the fire wall and welded the hole shut. Then made a small hole and ran the chassis wires forward and back along the frame rail.
See pics.

You get What I’m saying. Maybe if I call AAW they can help. Nice Pics,love the hidden look. Here’s mine

LS short box · 09-15-2024, 04:14 PM

Thanks for the kind words.
In regards to the ECM harness I punched a hole in the fire wall behind the right cylinder just low enough so I missed the heater box. I mounted the ECM and fuse holder behind the glove box. Had to section the glove box a bit to make room.
In the pic of the right hand side of the engine you can just see the Painless fuse holder. That wire goes to the fuse block.
Just for fun a pic of my latest 80 Camaro with a LS3 swap. Again tried to hide as many wires as possible.

**mongocanfly** · 09-15-2024, 04:58 PM

In your original message you didnt really specify what you needed a harness for.
so alot of assuming took place
Ive got a mixture..
My LS is running a PSI harness..the LS needs its own dedicated harness, but is easily tied into the truck harness...my 81 still has the factory harness on the truck side
My other truck also uses a PSI for the LS, but the truck side is the AAW..
The aaw harness can be ordered by how many circuits that you need..
If you need the truck side , make a list of all your electrical, I'm sure whoever you decide on would be happy to direct you to what you need
If your needing the LS harness ,there are several good ones on the market..my only complaint on the PSI is the harness is to short to allow the ecm to be mounted under the seat... BP makes their harness longer so it can be hidden under the seat..I'm using BP on my next one

LS short box · 09-15-2024, 08:38 PM

On my LS swaps I've used Speartech and Howell with both suppling a ECM with a base tune and wiring harness. If you send them your engine specs/trans details they can load a program that will get you running.
One thing I have gone away from on the last few LS swaps is the plastic "convuluted" wire cover and have been using the plastic braided wire cover. I get the generic stuff from Summit.
Hey Short Wide. I would look into moving the air filter so when your fans turn on they won't push air into the intake. Maybe it won't be a problem?
Company in WA state Intakehoses.com has a huge selection of rubber and alum tubing.

**1970 CST Short Wide** · 09-15-2024, 11:27 PM

Lots of good input. I’m not up on wiring or reading wiring blueprints. I have a stand alone harness for the LS that I bought years ago from Hot Rod Harness’s in LA. The A1 Electric window kit has its own harness as does the Dakota Digital Dash so I’m GUESSING I’d be just re wiring stuff like Lights and radio ?? Maybe I need to re think this

LS short box · 09-16-2024, 05:25 PM

Just FYI. I suck at wiring. If I can figure out the wiring you can. LOL.

REDROCKER652002 · 09-17-2024, 03:30 AM

My son and I rewired his 69 when we first bought it. I started with Painless and found that there were a lot of wires mounted to the same place on the fuse block and the instructions were very difficult. I looked into more options and found American Auto Wire to be the best. We had some grounding issues, but that was on me and not running the proper grounds to the proper places. Once I got that worked out, it all seemed to work out really well.

I have since "acquired" my dad's 56 Belair when he passed. None of my brothers wanted it so I took it over. It has been redone somewhat, but I might rip all the wiring out and use the AAW kit for that as well.

09-12-2024, 10:01 PM	#1
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,188	Thinking about re wiring Who makes the best harness What are guys using as far as re wiring harness kits. I’ve heard of American Wire and Painless. Are there any more out there. Would like to hear suggestions Thanks __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

09-12-2024, 10:05 PM	#2
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: Thinking about re wiring Who makes the best harness I used American Autowire..and will use them in the future ..very nice kit Have a buddy that's used kwikwire on several of his.. __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

09-13-2024, 07:41 AM	#3
A1971Blazer Senior Member Join Date: Nov 2013 Location: East Tennessee Posts: 2,199	Re: Thinking about re wiring Who makes the best harness I used the M&H upgrade kit on my '67 with great success. __________________ 1967 C10 Step side 1968 C10 Step side 1970 Chevrolet K/5 Blazer 1972 Chevrolet K/5 Blazer .............

09-13-2024, 10:31 AM	#4
Sheepdip Senior Member Join Date: Nov 2018 Location: Waterford California Posts: 2,628	Re: Thinking about re wiring Who makes the best harness My boy used Painless and it was straight forward and pretty simple or at least I thought so.

09-13-2024, 11:17 AM	#6
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,637	Re: Thinking about re wiring Who makes the best harness I've used a Painless kit before and it was anything but, plus a lot of undersized wires. American Auto Wire has been my go to for the past 3 kits

09-13-2024, 11:28 AM	#7
Boog laying low Join Date: Mar 2001 Location: Searcy, Ark. USA Posts: 13,526	Re: Thinking about re wiring Who makes the best harness Aaw. __________________ Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross

09-13-2024, 11:45 AM	#8
biketopia Senior Member Join Date: Jul 2015 Location: Warrenton VA Posts: 1,106	Re: Thinking about re wiring Who makes the best harness I have an AAW for my project. My brother installed one of there kits in his 70 Camaro and prefered it over the previous Painless kits he's used. Some of the "update" stuff is modern blade type fuses and relays for headlights. https://67-72chevytrucks.com/vboard/...d.php?t=642579 __________________ 71 c-10 Long Bed, under the knife for a No Limit Engineering Wide Ride Chassis Pack and coil over static drop. 07 Silverado Classic 2wd 95 Camaro 427SBC/TH350

09-13-2024, 04:19 PM	#9
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,134	Re: Thinking about re wiring Who makes the best harness I used Painless on my hot rods that needed a total rewire. They worked well. I used the 21 universal kit. Not the direct fit kits.

09-13-2024, 07:00 PM	#10
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,375	Re: Thinking about re wiring Who makes the best harness Are you doing a plug and play stock replacement or do you have major changes in mind? __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

09-14-2024, 01:07 AM	#11
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,188	Re: Thinking about re wiring Who makes the best harness My Big ? Is I have Dakota Digital, Vantage Air, A1 Power windows, LS1 Computer which all have there own harness. So what am I really Re Wiring __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

09-14-2024, 09:37 AM	#12
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Thinking about re wiring Who makes the best harness i built a custom truck using a squarebody drivetrain with a 51 international as the body. I used American Auto Wire and the harness is great and easy to install __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

09-14-2024, 04:33 PM	#14
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,134	Re: Thinking about re wiring Who makes the best harness The LS ECM will need 12 volts constant and 12 volts in start and run when you turn the key. Your LS harness should include a fan relay and fuel pump relay. I assume you will need a relay for the power windows. Same with the AC circuit. Gauges I'm thinking 12 volts in key on and run. Check with Dakota if it needs a constant 12 volt. You have so much aftermarket stuff a direct fit harness would be a waste of money if its a lot more money than a universal kit IMO. I love to hide wires. So on my 68 project I moved the Painless fuse block away from the fire wall and welded the hole shut. Then made a small hole and ran the chassis wires forward and back along the frame rail. See pics. Attached Images

09-15-2024, 04:14 PM	#16
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,134	Re: Thinking about re wiring Who makes the best harness Thanks for the kind words. In regards to the ECM harness I punched a hole in the fire wall behind the right cylinder just low enough so I missed the heater box. I mounted the ECM and fuse holder behind the glove box. Had to section the glove box a bit to make room. In the pic of the right hand side of the engine you can just see the Painless fuse holder. That wire goes to the fuse block. Just for fun a pic of my latest 80 Camaro with a LS3 swap. Again tried to hide as many wires as possible. Attached Images

09-15-2024, 04:58 PM	#17
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: Thinking about re wiring Who makes the best harness In your original message you didnt really specify what you needed a harness for. so alot of assuming took place Ive got a mixture.. My LS is running a PSI harness..the LS needs its own dedicated harness, but is easily tied into the truck harness...my 81 still has the factory harness on the truck side My other truck also uses a PSI for the LS, but the truck side is the AAW.. The aaw harness can be ordered by how many circuits that you need.. If you need the truck side , make a list of all your electrical, I'm sure whoever you decide on would be happy to direct you to what you need If your needing the LS harness ,there are several good ones on the market..my only complaint on the PSI is the harness is to short to allow the ecm to be mounted under the seat... BP makes their harness longer so it can be hidden under the seat..I'm using BP on my next one __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

09-15-2024, 08:38 PM	#18
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,134	Re: Thinking about re wiring Who makes the best harness On my LS swaps I've used Speartech and Howell with both suppling a ECM with a base tune and wiring harness. If you send them your engine specs/trans details they can load a program that will get you running. One thing I have gone away from on the last few LS swaps is the plastic "convuluted" wire cover and have been using the plastic braided wire cover. I get the generic stuff from Summit. Hey Short Wide. I would look into moving the air filter so when your fans turn on they won't push air into the intake. Maybe it won't be a problem? Company in WA state Intakehoses.com has a huge selection of rubber and alum tubing.



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09-15-2024, 11:27 PM	#19
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,188	Re: Thinking about re wiring Who makes the best harness Lots of good input. I’m not up on wiring or reading wiring blueprints. I have a stand alone harness for the LS that I bought years ago from Hot Rod Harness’s in LA. The A1 Electric window kit has its own harness as does the Dakota Digital Dash so I’m GUESSING I’d be just re wiring stuff like Lights and radio ?? Maybe I need to re think this __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

09-16-2024, 05:25 PM	#20
LS short box Registered User Join Date: Jun 2015 Location: Carlos MN Posts: 2,134	Re: Thinking about re wiring Who makes the best harness Just FYI. I suck at wiring. If I can figure out the wiring you can. LOL.

09-17-2024, 03:30 AM	#21
REDROCKER652002 Registered User Join Date: Nov 2018 Location: South San Francisco CA, Posts: 441	Re: Thinking about re wiring Who makes the best harness My son and I rewired his 69 when we first bought it. I started with Painless and found that there were a lot of wires mounted to the same place on the fuse block and the instructions were very difficult. I looked into more options and found American Auto Wire to be the best. We had some grounding issues, but that was on me and not running the proper grounds to the proper places. Once I got that worked out, it all seemed to work out really well. I have since "acquired" my dad's 56 Belair when he passed. None of my brothers wanted it so I took it over. It has been redone somewhat, but I might rip all the wiring out and use the AAW kit for that as well.

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