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external voltage regulator conversion to a new alternator/regulator in my 1970 chevel

23990 Views 6 Replies 4 Participants Last post by  EOD Guy
I followed directions from the internet and jumpered the blue and brown wires together at the old location of the external regulator, and then capped off the yellow and orange wires at that location. Then at the alternator end I ran the blue wire that came from the brown/blue connection into the number 1 pin of the new alternator and a red jumper to the number 2 pin from the battery connection. and just capping off the yellow wire. Upon starting the engine and checking voltage I have 13.7 volts which is excellent. the problem I have is WITH THE KEY IN THE OFF POSITION, MY GENERATOR LIGHT ON THE DASH REMAINS ON. Then when I turn the key to the on position before starting the light will go off. Can someone help me with this, and have a diagram of what i must be missing. Thanks.
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Here is the conversion dia. For some reason you are the second person that's followed the internet version and has had trouble.


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Thanks EOD I will give this hookup a try on my chevelle, I'll let you know if i got it right.
Make sure you double check the#1 and #2 connector for orinetation, I didn't and ended up reversing them and it cost me a battery and an alt before I figured it out
I did it the same as eod guy's attachment and had exactly the same problem. I thought it might be because the alternator was self exciting. I have 12v at terminals #1 & #2. This was on a 67 Firebird.

Blue and brown spliced together with the blue wire going to the #1 terminal on the alt. (brown wire is the exciter wire, tied to the idiot light, and tells the alt to start putting out juice)

Red and White spliced together with the red wire going to the #2 terminal on the alt (white wire is the sense wire and tells the alt to put out more or less juice depending on the elec demand on the system).
You can run a jumper wire from the lg lug on the back of the alt to the #2 terminal and create a one wire alt...... I'm not a fan on doing this because #2 terminal is the sense wire. GM took advantage of the long run of wire from the #2 terminal all the way over to the voltage reg for resistance and the alt gets a truer sense for the demand etc....

You need to run at least a 10 gauge from the junction terminal on the radiator support over to the horn relay in conjunction with the old wire already there. Before my re-wire, I ran a new 8 gauge from the lg lug on the alt to the horn relay and a 8 gauge from the horn relay to the junction terminal then an 8 gauge to the battery........ I did this because the junction terminal actually melted and I didn't want a complete melt down……. soon after I did the re-wire and protected the whole system with a 70 amp maxi fuse.
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