bo:

The wire from the D+ terminal on the alt. (blue/white, changing to blue) will be wired to one side of the charge indicator light of the instrument panel IF that indicator light has 12V+ supplied to the other side with KeyOn. When the key is on, engine off, the light will be on because a ground exists through the alt. diodes. When the engine is running, and the alt, is charging, both sides of the indicator light will be at 12V+, and no current flows, so the light is off.

If the indicator is not wired as above, get a diagram for the vehicle, and perhaps we can figure some way to provide charging indication.