Classic/Antique Car Repair: Voltage regulator wiring, beetle volkswagen, internal regulator

Question
QUESTION: Hi Rick,

I have a 1978 Super Beetle Volkswagen Convertible in restored condition.  I am replacing the voltage regulator.
You sent me the wiring instructions for the new voltage
regulator (Bosh 9 190 040 099E), thanks.  The original
voltage regulator has never been replaced.  I looked at it,
and it is smaller in size and has a date stamp 1977. I
looked at the Bentley's VW manual wiring section and tried to compare the current wires with the new regulator
connections, which makes some sense.  But when I looked at
the original voltage regulator, the connections are not
clear what wire goes with what. Can you provide some
guidance how the current wires hook up with the new voltage
regulator?  I read if you do not wire the voltage regulator
correctly, you can cause some serious electrical problems.

Thanks,
Dennis...

ANSWER: Dennis,
 Sorry for the delay.  I was down sick for a few days.  
I am curious as to why you have an alternator with a separate regulator.  Beginning in late 1974, the originally installed  alternators came with an integral (internal) regulator.  

Rick

---------- FOLLOW-UP ----------

QUESTION: Rick,

The voltage regulator is under the rear seat on the left
side.  So I am not sure what you mean about the alternator?
As you know, the alternator has the fan belt on it and on
top of it are 2 wires labeled DF and D+ that are connected
to the voltage regulator.  I think I can trace these wires
to the voltage regulator.  These are bundled and go through
a hole on the back left side of the rear seat.  So any
help in telling how to compare the original voltage
regulator wires to the new voltage regulator would be
helpful.

As always, thanks again for your help.
Dennis...

Answer
Dennis,
 There are 3 possible configurations:
- Generator with external regulator, mounted under the rear seat.
- Alternator with external regulator mounted on the alternator housing.
- Alternator with an internal regulator (newest and simplest setup.)   

Therefore, if you have an external regulator under the seat, you most likely have a GENERATOR.  However it is not correct for what was originally installed for your year/model, which should be an INTERNALLY regulated ALTERNATOR.  

If you do have a generator, here is the proper wiring:
http://www.netlink.net/mp/volks/pics/gen.jpg

This diagram shows the correct wiring for an EXTERNALLY regulated alternator:
http://www.netlink.net/mp/volks/schem/altreg.gif

The correct regulator for this alternator is here:
http://www2.cip1.com/ProductDetails.asp?ProductCode=BOS-0-190-600-017

If you want to switch to the proper INTERNALLY regulated alternator, read this procedure (scroll down to "Converting from an External VR Alternator to One With an Internal VR")

http://www.vw-resource.com/alternator_wiring.html

Rick