IMO, unless the alternator is spec'd with the proper regulator for single wire service, DA#1 must be connected to a switched power supply for the unit to produce a charge. If a charge lamp is in that circuit then that's a plus, but not required.

10SI alternators with single wire 'self exciting' regulators need no connection through the DA plug (regulator).

If the alternator is purchased from a supplier based on application it will probably not have single wire capability. If it were purchased from a local auto electric rebuilder then it may have the 'either/or' regulator installed.

This has been my experinece.

http://www.weblube.com/10SI-regulators2.html

Stuart

Last edited by atomarc; 02/28/2010 12:06 AM.