Alternator Warning Light Not Coming On

1981 308. With the ignition switched on the alternator( battery) warning light is not coming on. The car will fire up and run fine with no problems. Have not driven it in a few weeks, nor since I noticed the light not coming on. I have checked the bulb and it is fine. Last time this happened it was on a 944 and the alternator was not charging. When I took the 944 alternator for a rebuild the tech told me the contacts were stuck open and I could have possibly temporarily fixed the problem by banging on the alternator with a wrench.

Any ideas on what to check? Is the regulator located inside the alternator? I think I recall the wiring diagram showing the completion of the warning light circuit coming of the regulator and from the top of fuse#3. I would just take the alternator out and rebuild it but as luck would have it ( for me and the new owner) I just sold the car and the next trip is a short one down the block in a few days to an enclosed transporter.

 

Thanks Paul, can you please tell me if the regulator is external or internal? If external where it's located?
Thanks!

 

Thanks Steve!