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Old 10-26-2019, 04:12 PM   #1
Perma71
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1971 Wiring Nightmare

Hello.
The wiring on this truck is completely screwed up. It was running when the engine was pulled, but I can’t figure out how it worked. The truck has an HEI, electric choke, and external regulated alternator. There is no plug for the alternator coming out of the harness...crazy. The black insulated wire is green.
I turned the key on, but have no voltage to any of the wires.
I’m not good with wiring and don’t want to screw this up anymore than it is.
How do you think it goes?
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Last edited by Perma71; 10-26-2019 at 04:22 PM.
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Old 10-26-2019, 05:26 PM   #2
RustyPile
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Re: 1971 Wiring Nightmare

If your truck ran before the engine removal, something happened at that time that created your problem.. No disrespect meant but posting a picture of a wad of wires isn't much for us to go on..

This site has an electrical forum. One of the sticky threads in that forum is a posting of downloadable wiring diagrams.. Go there, and download the wiring diagram for your truck.. Trace out and locate the flow of electrons path".. You can then post questions requesting more specific information. As for electric chokes, upgrading to internal regulated alternators, HEI installations, those subjects have been covered in several threads.. Use the site's search feature for that information.. This site is a great place for help with the problems on these old trucks.. You just have to be more specific with "what ails your truck"...
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Old 10-26-2019, 06:20 PM   #3
Perma71
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Quote:
Originally Posted by RustyPile View Post
If your truck ran before the engine removal, something happened at that time that created your problem.. No disrespect meant but posting a picture of a wad of wires isn't much for us to go on..

This site has an electrical forum. One of the sticky threads in that forum is a posting of downloadable wiring diagrams.. Go there, and download the wiring diagram for your truck.. Trace out and locate the flow of electrons path".. You can then post questions requesting more specific information. As for electric chokes, upgrading to internal regulated alternators, HEI installations, those subjects have been covered in several threads.. Use the site's search feature for that information.. This site is a great place for help with the problems on these old trucks.. You just have to be more specific with "what ails your truck"...
Figured out the alternator. Not sure about the green wire with the rubber jacket.
I didn’t take the wiring apart. I just put the engine and trans back in. All the plugs are gone and have been replaced with spade connectors.
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Old 10-26-2019, 06:44 PM   #4
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Re: 1971 Wiring Nightmare

Quote:
Originally Posted by Perma71 View Post
Figured out the alternator. Not sure about the green wire with the rubber jacket.
I didn’t take the wiring apart. I just put the engine and trans back in. All the plugs are gone and have been replaced with spade connectors.
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I'm a GM certified (retired 1993) electrical technician. The electrical in these old trucks is "right up my alley". I teach like I was taught. I don't spoon feed information.. When you get your hands on that wiring diagram and make some attempts to learn the purpose of that green wire, but can't figure it out, I'll be glad to walk you through learning that..

Green is a color used in engine function monitoring, and among other functions, it's also used in lighting circuits.. The wiring diagram will aid you in determining exactly what your specific wire does... As I previously stated, I can't tell from your single picture, but just looking at your picture, I don't believe the HEI installation/modification was properly done to the wiring..
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Old 10-26-2019, 07:07 PM   #5
Perma71
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Quote:
Originally Posted by RustyPile View Post
I'm a GM certified (retired 1993) electrical technician. The electrical in these old trucks is "right up my alley". I teach like I was taught. I don't spoon feed information.. When you get your hands on that wiring diagram and make some attempts to learn the purpose of that green wire, but can't figure it out, I'll be glad to walk you through learning that..

Green is a color used in engine function monitoring, and among other functions, it's also used in lighting circuits.. The wiring diagram will aid you in determining exactly what your specific wire does... As I previously stated, I can't tell from your single picture, but just looking at your picture, I don't believe the HEI installation/modification was properly done to the wiring..
Everything is messed up. The yellow to the coil continues with another spade that I think went to the electric choke on the Carter. Those diagrams are tough to see on my little phone.
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Old 10-26-2019, 07:27 PM   #6
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Re: 1971 Wiring Nightmare

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Everything is messed up. The yellow to the coil continues with another spade that I think went to the electric choke on the Carter. Those diagrams are tough to see on my little phone.
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You don't have a "full screen computer?? Can your phone be interfaced with a regular sized monitor??? Can you not print off a copy of the diagrams??? Do you have access to the internet besides your phone??? Smart phones have their place in our modern technology.. Viewing schematics, wiring diagrams, and other highly detailed pdf, etc based information isn't one of their uses...

The "yellow to the coil" all the way back to the starter solenoid should have been completely removed as part of the HEI installation.. There are one or two correct ways to supply power to an HEI unit.. There are numerous, numerous ways to do it wrong.. Some will work, most won't..
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Old 10-26-2019, 06:49 PM   #7
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Re: 1971 Wiring Nightmare

If the green wire (Light green) has a woven black tar like sleeve covering it most likely the wire for the temperature switch or sender if you have guages. See photo but ignore the yellow wire coming out of the sleeve as that goes to my electric choke which wasn't installed when the photo was snapped.
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Old 10-26-2019, 07:13 PM   #8
RustyPile
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Re: 1971 Wiring Nightmare

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If the green wire (Light green) has a woven black tar like sleeve covering it most likely the wire for the temperature switch or sender if you have guages. See photo but ignore the yellow wire coming out of the sleeve as that goes to my electric choke which wasn't installed when the photo was snapped.
HO455, I would never question your knowledge of these old trucks. I have seen you "in action" when solving a problem for someone. You know your stuff. But it's obvious Perma71 isn't very familiar with the various electrical circuits of them.. He needs to learn this area in particular as the wiring and electrical components are the items most prone to failure.. Spoon feeding information and promoting guess work does nothing toward their "education".. You and I know exactly the function of a green wire protected by a sleeve. Especially if it's in the vicinity of the engine. But according to Perma71, the wiring is "messed up".. Who's to say that wire hasn't been repurposed for another use???.. Our blurting out the answer won't stick with the "student" near as well as when he has to do some of the searching himself...
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