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Old 02-09-2013, 11:22 PM   #1
71badblue
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alternator wire up

i have a 1971 c-10 with the wiring harness chopped up. i am trying to wire in a internally regulated alternator, my question is where do the wires in the two wire plug need to be connected to make it work properly thanks in advance for all your help
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Old 02-10-2013, 12:23 AM   #2
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Re: alternator wire up

This is how I did mine but it depends on whether you have the idiot light dash or the gauge dash. It also depends on how chopped up your harness is and what wires are cut or missing.

If you still have the external voltage regulator and the wiring then you can use this diagram.

This is how the stock wiring looks. It is for the gauge cluster dash with the battery gauge.

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this is how the internal regulated alternator is wired.

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The brown wire is jumpered to the white wire and goes to the no.1 terminal on the new alternator.
The red wire is jumpered to the blue wire and goes to the no. 2 terminal on the new alternator.
The larger red output wire on the back of the alternator can be left alone and connected to the three way junction with the smaller red wire that jumpers to the blue wire from the external regulator.

This is the clean way to do it and the connections all end up the same.
If you mount the alternator on the passenger side of the engine like I did then you will have to extend the brown and small red wires and the larger red charging wire to reach the three way junction.
The brown wire that used to go to the external regulator originates at the key switch and goes through the firewall block and then to the regulator. It is a 16 gauge wire and should be easy to find. Notice that it goes to the firewall block in all three diagrams. Your battery gauge or idiot light should work in all three cases.

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Old 02-10-2013, 01:43 PM   #3
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Re: alternator wire up

i still have the voltage regulator and the wiring that comes off of it is only about a foot long, the rest has been cut
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Old 02-10-2013, 10:51 PM   #4
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Re: alternator wire up

so what's your next move?
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Old 02-11-2013, 02:51 PM   #5
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Re: alternator wire up

i guess im gonna have to order the harness thru lmc and then wire it up using ur diagram
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Old 02-15-2013, 01:27 AM   #6
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Re: alternator wire up

You should not have to order a harness from LMC just to switch to an internal voltage regulator even if there is only a foot left. Go get some wire from your parts store or home improvement store and use the diagrams above. I would solder the splices but you could use some crimps. Look at the size wire you are splicing into and try to get the same color and guage and it will look better, perform better, and make it easier to understand in the future incase you or the next owner need to get back in there.

Good thread here

I am fixing some wiring on one of mine right now and one circuit goes from black to red to blue, with like 5 crimps and differnt guage wires in that 4 foot span. Talk about confusing...
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Old 02-15-2013, 12:55 PM   #7
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Re: alternator wire up

i have the idiot light dash. i see no brown wire.
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Old 02-15-2013, 06:26 PM   #8
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Re: alternator wire up

Quote:
Originally Posted by ChevyCruizer View Post
Good thread here

I am fixing some wiring on one of mine right now and one circuit goes from black to red to blue, with like 5 crimps and differnt guage wires in that 4 foot span. Talk about confusing...
I wired mine using toddtheodd's method and it worked great!
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Old 02-15-2013, 08:02 PM   #9
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Re: alternator wire up

Connecting the sensing wire to the large wire on the back of the alternator will work but it is more efficient to do it like the diagram in my post.
This website explains it in detail if you care to read it.

......http://www.madelectrical.com/electri...esensing.shtml
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Old 02-18-2013, 04:32 PM   #10
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Re: alternator wire up

gene after u wired up the alternator did u plug the voltage regulator back in? and do i need to run the wire that hooks into the stud with the bolt to the postive side of my battery?
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Old 02-21-2013, 04:51 PM   #11
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Re: alternator wire up

No, dont plug the external reg back in, there is one built into the new alternator.

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gene after u wired up the alternator did u plug the voltage regulator back in? and do i need to run the wire that hooks into the stud with the bolt to the postive side of my battery?
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Old 02-21-2013, 08:26 PM   #12
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Re: alternator wire up

Quote:
Originally Posted by 71badblue View Post
gene after u wired up the alternator did u plug the voltage regulator back in? and do i need to run the wire that hooks into the stud with the bolt to the postive side of my battery?
No, the external regulator is not used anymore. Don't remember the particulars but you run a jumper at the plug. Follow the instructions in that thread and you'll be pleased.
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