When the ignition is on, without the engine running, my alternator isn't pulling "exciter" current from the idiot lights in the instrument cluster. I know it's not the cluster or wiring, because if I pull the wire from the "61" connector on the alternator, and then ground that wire, the expected idiot lights come on.

My question is about the voltage regulator / brushes module.
- the innermost brush surface on this module, has continuity through to a contact point that mates with a springy metal tab inside the alternator, when installed.
- from the outermost brush surface, however, I would have expected there would be continuity through to the ground connection where the screw secures the module. I get no continuity, however, between the ground point on the module, and any other point inside the module.

Does this mean the module is defective? What resistance value should I expect to see between the module's ground point and one of the brushes?

I didn't check, but does anyone know if the springy metal tab inside the alternator connects through to the external "61" or "D+" connection? (A detailed alternator / voltage regulator wiring diagram would be great!)

I did check the resistance on the slip ring contact points for the winding on the rotor, and it was around 3 ohms (2k range setting), so I'm still suspecting that my problem is indeed the voltage regulator module.

I'm trying to avoid buying the module, only to find that the problem is elsewhere inside the alternator, since most outfits won't take returns on electrical items. (If I can, I will try to do this continuity test on the new module before purchasing it).

Thanks,


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David Armstrong - '86 240(350k km?), '93 940T(270k km), '89 240(parts source for others) near Toronto