Alternator warning light problem.
 

1985 Euro Cab.

I am troubleshooting a no-charge problem...battery is fully charged and the alternator warning bulb is good, but bulb does not light when key is on. If I ground the bulb with the key on, it lights.

I disconnected the 14 pin connector in the engine compartment and I have continuity between the male post of the D+ (blue) and the blue wire at the Alt. warning light.

I do not have continuity from ground to the female D+ blue wire on the 14 pin connector...should there be continuity?

If so, next step is alt. removal.

I had this problem a shortly after I bought my '84 a few weeks ago. In my case, it was a failed voltage regulator (which mounts on the back of the alternator).

http://forums.pelicanparts.com/porsche-911-technical-forum/638714-84-carrera-elect-failure-car-towed-come.html

+1 for VR...

easy to test that first IMO

The path to ground from the warning lamp is through the blue wire, VR, brushes and slip rings on the rotor inside the alternator. The VR seems the most suspect for your lack of continuity to ground.