replace wiring? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**69Tom** · 02-15-2018, 03:04 PM

So I have a general question. I'm about to receive shipment of my 70 C/10 soon. I was wondering what people's thoughts are about replacing the dash wiring harness for safety and reliability purposes.

I have another vintage vehicle and I'm having all kinds of electrical issues with it at the moment. I didn't replace the harness (mainly because I'd have to have it specially made--there's no one who carries them), and I'm kind of now regretting it.

With the addition of installing a radio and a Vintage Air system to the truck, I'm kind of thinking of pulling the plug on a new Lectric Limited harness might be a good idea. Also, I have a OEM factory gauge set up that I'm considering adding to the truck, so the new harness makes sense in this setting.

Thoughts?

**VetteVet** · 02-15-2018, 03:45 PM

Based on what you said I think you would be better off buying a upgrade harness from Painless or any of the major players, that would accommodate Most of the mods that 67 to 72 trucks need. they can provide wiring for HEI ignition and internally regulated alternators,and probably headlight relay harnesses as well.
One thing for sure, get a quality junction buss bar or a new style fuse panel or both.
Then run the Vintage air off a standalone harness. Depending on the radio I.E normal replacement, or high volume stereo, you'll need to power them off the fuse box or the buss bar. If it's a HV stereo i'd use a stand alone harness on it too.

Coolant fan(s) can be included in aftermarket harnesses if you want to pay extra.

If you need help on any of the wiring, you're in the right place.

**69Tom** · 02-15-2018, 03:51 PM

Thanks. I have been advised that it might be a good idea to go with the Classic Update Wiring Harness from American Autowire. While not cheap, it seems like a good idea. Not being able to use the ammeter is annoying (I have contacted TBone1964 for a voltmeter gauge), but that's about it.

Dead Parrot · 02-15-2018, 04:53 PM

2nd on the new harness. Sounds like you plan on replacing/modifying a bunch of it anyway. I think I read new gauges instead of idiot lights, radio, AC, possible audio amp, etc. That would be a lot of splices to the 47 year old harness that who knows what previous owners have already modified.

Get one setup for all of the stuff you plan on adding.

**69Tom** · 02-15-2018, 04:57 PM

Thanks.

Well, I just pulled the trigger. Got an American Autowire harness through MCB Parts for $475 shipped. Seems like a pretty good deal vs. prices I saw online. This will cover under dash harness and engine bay as well.

I read that I need a single prong alternator and an HEI system with this. That shouldn't be too big of a deal to get.

**VetteVet** · 02-15-2018, 07:52 PM

Quote:

Originally Posted by 69Tom

Thanks.

Well, I just pulled the trigger. Got an American Autowire harness through MCB Parts for $475 shipped. Seems like a pretty good deal vs. prices I saw online. This will cover under dash harness and engine bay as well.

I read that I need a single prong alternator and an HEI system with this. That shouldn't be too big of a deal to get.

You shouldn't have to settle for a one-wire alternator and the HEI wiring should be part of the harness. The HEI distributor only requires a key on, 12 volt source wire to make it operate. The ammeter wires should be included in the harness if it is designed for a gauge cluster truck.

*gmachinz* · 02-17-2018, 11:44 AM

The thing is most vendors are salesmen and not actual installers or have hands on experience. He/they should have asked you specific questions like amp draw expectations, CS/SI style alt? What kind of accessory setup are you running etc? I prefer the GM 3-wire alternators for reliability and I don’t subscribe to all the 1-wire alternators people try to shove onto people just because they try to say its easier to install/wire.

**69Tom** · 02-17-2018, 01:48 PM

Well I am planning on installing a vintage air system and a stereo in the truck. Way down the road I may consider an LS swap. It seems like the American Autowire harness has gotten good reviews from members. Is that not true? I can always return it once I get it

GM man · 02-22-2018, 01:29 PM

69Tom, I understand the desire to replace your harness, but is your original in bad shape? Both of my '72s have the original dash harnesses and both are in great condition. But new ones can give you peace of mind. I just finished an LS swap on my Jimmy and installed a Vintage Air unit. The wiring on the VA is as straight forward and easy as it gets. Are you just doing the dash harness or new wiring for the entire truck?

**69Tom** · 02-22-2018, 01:32 PM

Quote:

Originally Posted by GM man

69Tom, I understand the desire to replace your harness, but is your original in bad shape? Both of my '72s have the original dash harnesses and both are in great condition. But new ones can give you peace of mind. I just finished an LS swap on my Jimmy and installed a Vintage Air unit. The wiring on the VA is as straight forward and easy as it gets. Are you just doing the dash harness or new wiring for the entire truck?

I am planning on new wiring for the entire truck. I guess I have a few reasons for it. One, I just restored an old Fury and didn't replace the wiring in it. While it's not horrible, I've had a few issues with it, that have given me cause for concern. Two, this truck is somewhat rust and the wiring somewhat brittle. I would just feel better putting a new system in so I don't have to worry about it, especially with the new AC and stereo system going in there.

*gmachinz* · 02-27-2018, 12:39 AM

AAW is good stuff-nothing absolutely black/white from them and Painless, etc. A new harness is definitely a good investment but just be sure ahead of time what mods you want to plan for. Awhile back (several years in fact) a local bodyshop owner had a “mechanic” install his AAW chassis harness on his 57 Nomad. Well, there were many detail things I didnt like about the crimping aspects as a harness builder myself and while the basic layout was nice, the kits do not cover various looming, retaining clips, fasteners, etc that make the job look complete-so the installer often is left with trying to figure out what to do.

Then there were circuit issues with the tri-five update kit which I had to address such as the power window and cooling fan mods. The kit provides 1 hot “for power windows” but obviously AAW has no way of knowing what people actually need-in my case that power lead feeds a relay bank and that relay bank operates a set of aftermarket window motors which I outfitted with my GM auto down/up kit. AAW has no actual power window/lock harnesses-just hot feeds for them-arg.

Then they have 1 damn relay out of the fuse panel for an “electric fan”....well that wont work either. That Nomad has a fairly wild 383 and tends to run a bitbwarm so I built an LT1 dual fan kit and controlled it with my 3-speed conversion harness kit-and it uses a total of 4 relays w/AC override so again theres is useless.

My point is before installing their harness make sure you cover ALL your bases on your truck-I ended up having to modify the AAW harness so much in different areas it would have almost been easier to assemble a new harness from scratch.

02-15-2018, 03:04 PM	#1
69Tom Senior Member Join Date: Jul 2015 Location: Phoenix, AZ Posts: 1,333	replace wiring? So I have a general question. I'm about to receive shipment of my 70 C/10 soon. I was wondering what people's thoughts are about replacing the dash wiring harness for safety and reliability purposes. I have another vintage vehicle and I'm having all kinds of electrical issues with it at the moment. I didn't replace the harness (mainly because I'd have to have it specially made--there's no one who carries them), and I'm kind of now regretting it. With the addition of installing a radio and a Vintage Air system to the truck, I'm kind of thinking of pulling the plug on a new Lectric Limited harness might be a good idea. Also, I have a OEM factory gauge set up that I'm considering adding to the truck, so the new harness makes sense in this setting. Thoughts?

02-15-2018, 03:45 PM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,703	Re: replace wiring? Based on what you said I think you would be better off buying a upgrade harness from Painless or any of the major players, that would accommodate Most of the mods that 67 to 72 trucks need. they can provide wiring for HEI ignition and internally regulated alternators,and probably headlight relay harnesses as well. One thing for sure, get a quality junction buss bar or a new style fuse panel or both. Then run the Vintage air off a standalone harness. Depending on the radio I.E normal replacement, or high volume stereo, you'll need to power them off the fuse box or the buss bar. If it's a HV stereo i'd use a stand alone harness on it too. Coolant fan(s) can be included in aftermarket harnesses if you want to pay extra. If you need help on any of the wiring, you're in the right place. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. Last edited by VetteVet; 02-15-2018 at 07:44 PM.

02-15-2018, 03:51 PM	#3
69Tom Senior Member Join Date: Jul 2015 Location: Phoenix, AZ Posts: 1,333	Re: replace wiring? Thanks. I have been advised that it might be a good idea to go with the Classic Update Wiring Harness from American Autowire. While not cheap, it seems like a good idea. Not being able to use the ammeter is annoying (I have contacted TBone1964 for a voltmeter gauge), but that's about it.

02-15-2018, 04:53 PM	#4
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,472	Re: replace wiring? 2nd on the new harness. Sounds like you plan on replacing/modifying a bunch of it anyway. I think I read new gauges instead of idiot lights, radio, AC, possible audio amp, etc. That would be a lot of splices to the 47 year old harness that who knows what previous owners have already modified. Get one setup for all of the stuff you plan on adding.

02-15-2018, 04:57 PM	#5
69Tom Senior Member Join Date: Jul 2015 Location: Phoenix, AZ Posts: 1,333	Re: replace wiring? Thanks. Well, I just pulled the trigger. Got an American Autowire harness through MCB Parts for $475 shipped. Seems like a pretty good deal vs. prices I saw online. This will cover under dash harness and engine bay as well. I read that I need a single prong alternator and an HEI system with this. That shouldn't be too big of a deal to get.

02-17-2018, 11:44 AM	#7
gmachinz Account Suspended Join Date: Jun 2011 Location: Des Moines, IA. Posts: 4,143	Re: replace wiring? The thing is most vendors are salesmen and not actual installers or have hands on experience. He/they should have asked you specific questions like amp draw expectations, CS/SI style alt? What kind of accessory setup are you running etc? I prefer the GM 3-wire alternators for reliability and I don’t subscribe to all the 1-wire alternators people try to shove onto people just because they try to say its easier to install/wire.

02-17-2018, 01:48 PM	#8
69Tom Senior Member Join Date: Jul 2015 Location: Phoenix, AZ Posts: 1,333	Re: replace wiring? Well I am planning on installing a vintage air system and a stereo in the truck. Way down the road I may consider an LS swap. It seems like the American Autowire harness has gotten good reviews from members. Is that not true? I can always return it once I get it

02-22-2018, 01:29 PM	#9
GM man Registered User Join Date: Aug 2011 Location: Gainesville, Texas Posts: 127	Re: replace wiring? 69Tom, I understand the desire to replace your harness, but is your original in bad shape? Both of my '72s have the original dash harnesses and both are in great condition. But new ones can give you peace of mind. I just finished an LS swap on my Jimmy and installed a Vintage Air unit. The wiring on the VA is as straight forward and easy as it gets. Are you just doing the dash harness or new wiring for the entire truck? __________________ 1972 GMC Jimmy 6.0/4L65 1972 Chevrolet long bed 1/2 ton

02-27-2018, 12:39 AM	#11
gmachinz Account Suspended Join Date: Jun 2011 Location: Des Moines, IA. Posts: 4,143	Re: replace wiring? AAW is good stuff-nothing absolutely black/white from them and Painless, etc. A new harness is definitely a good investment but just be sure ahead of time what mods you want to plan for. Awhile back (several years in fact) a local bodyshop owner had a “mechanic” install his AAW chassis harness on his 57 Nomad. Well, there were many detail things I didnt like about the crimping aspects as a harness builder myself and while the basic layout was nice, the kits do not cover various looming, retaining clips, fasteners, etc that make the job look complete-so the installer often is left with trying to figure out what to do. Then there were circuit issues with the tri-five update kit which I had to address such as the power window and cooling fan mods. The kit provides 1 hot “for power windows” but obviously AAW has no way of knowing what people actually need-in my case that power lead feeds a relay bank and that relay bank operates a set of aftermarket window motors which I outfitted with my GM auto down/up kit. AAW has no actual power window/lock harnesses-just hot feeds for them-arg. Then they have 1 damn relay out of the fuse panel for an “electric fan”....well that wont work either. That Nomad has a fairly wild 383 and tends to run a bitbwarm so I built an LT1 dual fan kit and controlled it with my 3-speed conversion harness kit-and it uses a total of 4 relays w/AC override so again theres is useless. My point is before installing their harness make sure you cover ALL your bases on your truck-I ended up having to modify the AAW harness so much in different areas it would have almost been easier to assemble a new harness from scratch.



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