10SI Alternator Wiring

The 10SI has three terminals (including those with a 1 wire regulator).

And a dual terminal connector. (Repair pig-tails for this connector available at any autoparts store. Or, salvage with alternator if pulling the alternator from a vehicle).

If you are converting from a 3wire 10SI to a 1 wire regulator you can hook up all your stock connectors, and run it as is. However, thats wasted money unless you plan on cleaning out some wiring under your hood.

If the 1 wire is for cleaning out wires, you only need to retain the "BAT" wire. The #1 & #2 terminal wires can be eliminated. Don't be surprised to find that the #2 wire only goes a short way into the harness and spliced into the "BAT" wire.
The 1 wire regulator comes with a dust plug for the #1 & #2 terminals.


Some other tidbits available from AC Delco for wiring up a 10SI, is wiring package 1870921 (for those 6 to 12volt conversions). This contains the terminal connector AND an extra resistance wire pigtail to connect to the ignition system (don't use a ballast resistor if you use a resistance wire). Also available is an ammeter package (1965400).

Use a voltage guage to monitor your charging system. It will definately give you signs of impending problems. (Bad regulator, failing battery, etc.)

If your looking for a high output unit, keep an eye out for your everyday rebuilt (re-stamped 63amp). In my case, my rebuilt puts out 80amps at high rpm. More than enough for most needs.

High output aside, don't expect your alternator to do anything for you at idle speeds. Alternator output increases with rpm, even a 100amp unit won't put out much more than a 63amp unit at 1000rpm. If your using underdrive pulleys, this may highlight or worsen idle output problems.

Thanks to Jerry (d.j.sherrell@..........net) for pointing out some terminology errors I had in prior versions of this page.


This information is only intended as an overview and may not include all the necessary information, data, or facts.
Every vehicle is unique, and research for your particular vehicle is recomended.

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This Page Created By Alexander M. Bilan (gmguy89@netscape.net)
All Rights Reserved.
June 13, 1997
Revision 1.3 April 5,2003