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Hello:
I’m helping a friend restore a Duchess roadster that was originally built in 1980 and uses a 73 VW beetle platform. The wiring was so hacked up that we removed all of it and are rewiring it using a Speedway Motors 22 circuit wiring kit. The car does everything it’s supposed to except I can’t get it to charge. I suspect it’s in the way I wired the charge light but I’m at a loss to understand the concept. It did charge correctly before we de-wired it. I replaced the original Motorola voltage regulator with new and it’s using the original harness to connect to the alternator. I have it wired according to Speedy Jim’s drawing so that the blue wire from the charge light is tied into the red wire that connects to the d+ post on the alternator. the kit, which assumes you’re using a GM alternator, has a separate ignition activated circuit for exciting the alternator. I’m running that circuit through the charge light which came with the car, to the blue wire back to the regulator. I have it wired so that the main + battery cable connects to the lug on the starter and branches from there to the B+ terminal on the alternator and another branch runs to the fuse block under the dash. The dash is wood so I tried grounding the body of the charge light to the car to see if that made a difference which it didn’t. I’m sure I’m not the first person to have this issue so I humbly ask the forum for help.
I was wondering if any of you vw guys might have an idea what might be causing this issue ?
jkneipper there is a vw wiring diagram in the forum library under “vw manuals”
dreplica.com/wp-content/uploads/MiGi_II_Wiring_Harness.pdf
TDREPLICA Map
http://www.arcgis.com/home/webmap/viewer.html?webmap=7f9174ad614e43b680deba085b0abf48
I’ve looked at every wiring diagram I could locate including the one in the original kit instruction book which we were able to find and everything looks legit. Haynes manual wasn’t much help either. Is there a quick check of the alternator we can do without removing it from the car? That’s about the only thing I haven’t done yet. I don’t think the owner would go along with pulling it off and taking into the repair shop without some indication it’s bad. Thanks again.
jkneipper. There are two types of alternators. Older ones used an external voltage regulator. The newer alternators are internally regulated and do not require an external voltage regulator. Your 1st task would to be to find out if your alternator is internally regulated. If so, connect the wire from the DF terminal on the alternator directly to the warning bulb and be sure the bulb has a good ground. If it is NOT internally regulated, your regulator should have four terminals; D, DF, 61, B+ and a ground wire from the regulator to the ground screw on the alternator. Your DF wire on the alternator connects to DF on the regulator and from terminal 61 to the bulb. Again the bulb must be grounded. If that’s how things are wired you may have a bad regulator. My .02 cents worth anyway.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The Shack+1 to Allen, but I didn’t see that you replaced the alternator itself, only the regulator. If it worked with a regulator before, ergo the alternator itself is designed to work with the regulator. It was charging before with the old voltage regulator, the first thing I’d try would be to put the old regulator back in and see if it works. It’s possible that your wiring is fine but the new regulator itself is bad. Lots of new electronics are bad these days right out of the box.
The alternator has B+, DF, D+, & D- terminals. B+ goes to the battery. We are using the original VW harness between the regulator and alternator that has the original connectors on the ends so there shouldn’t be an issue. It wouldn’t charge with the old Motorola regulator either. The charge light does come on when the ignition is turned on but doesn’t go out with the engine running. Charge light is wired from the ignition through the light to the voltage reg where the blue wire and red wire are tied together in the VW harness and then on to the terminal on the alternator. The light will go out if I pull the connector off of the alternator so there is continuity there. Is the charge light of a special design? It has just a standard 2 wire panel light. And the dash is wood too.
“Special design?” Well, sort of a special design. The charge light was designed to come on when there was voltage across it. That in itself is not special, but how it hooked up was a bit different. One of it’s wires went to the generator (actually the regulator), the other to the B+ of the battery which may have come from any hot wire under the dash. So, when the generator was not charging there was voltage across the bulb (assuming a good battery). If the generator was generating, then you had 13+/- volts out of the generator on one side of the bulb and 13+/- volts on the other coming from the battery. Therefore the voltage difference ACROSS the generator light was zero and it would remain unlit. (The bulb itself is not “grounded” in the normal way, but it is through the regulator when the regulator senses that the generator is not putting out enough voltage.)
12 volts to it–there’s a terminal you have to hit while it’s running. Excite the alt.
https://www.youtube.com/watch?v=QPl7CTb685I
That sounds a lot like flashing the generator.
Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackWhen I put the Soob in Bridget the same thing happened. I’d wired in all the rigourmorole. All the engine wiring and the ECU and the extra stuff like the igniter and the various important looking electronic block thingies. And the tach. And the fans. All that. The engine ran.
The alt light was on.
It was a brandy-new alternator. I checked all the connections, Everything was good. Re-did grounds because that’s usually the problem. They were good. Nothing changed.
Finally—and this might have been accidentally—I touched the alt side of the alt light wire to a 12-v source, while the engine was running.
There was a deep sound and the idle dropped as the alternator came to life. The volt meter jumped from under 12 to over 14 volts. The light went out. It’s been out since…except it glows a little when the radiator fan runs, for reasons I can’t divine.
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