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broberson · 08-13-2019, 10:12 PM

After looking at some diagrams on the internet, I've found that the posts on the rear of the alternator are: 1 and 2, or R and F. The 2 post is jumped over to the battery post in the rear, and the 1 post is tied into the "idiot" light or charge indicator, and into the "dash harness brown Alternator Ign exciter connection wire (4A)on the main dash harness" according to the instructions from American Autowire.

The instructions do say that if you are using a one wire alternator, that this wire will not be used, and the only thing tied into the alternator will be on the positive post.

So my question goes back to why is my aftermarket tachometer not working now? It is plugged into the distributor with a plug, but no power I'm assuming because somehow the 4A plug isn't connected to the alternator.. I'm at a loss here..

08-13-2019, 10:12 PM	#5
broberson Registered User Join Date: Dec 2018 Location: Austin, TX Posts: 59	Re: 1970 C10 Alternator/wiring issue After looking at some diagrams on the internet, I've found that the posts on the rear of the alternator are: 1 and 2, or R and F. The 2 post is jumped over to the battery post in the rear, and the 1 post is tied into the "idiot" light or charge indicator, and into the "dash harness brown Alternator Ign exciter connection wire (4A)on the main dash harness" according to the instructions from American Autowire. The instructions do say that if you are using a one wire alternator, that this wire will not be used, and the only thing tied into the alternator will be on the positive post. So my question goes back to why is my aftermarket tachometer not working now? It is plugged into the distributor with a plug, but no power I'm assuming because somehow the 4A plug isn't connected to the alternator.. I'm at a loss here..