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Thu Nov 20, 2008 9:05 pm

I had an alternator that all of a sudden stopped working. I measured the voltage across it when the car was reved up and it was putting out battery voltage.

The battery was old, so I replaced the battery and I replaced the alternator. I revved it up with a voltmeter across it and it put out 14.50 volts. Problem solved right?

Today I was driving home from work and the dash lights started dimming, so did the headlights. I got off the highway and the car sputtered and died. I had to push it off of a divided highway.

I'm not sure where to start. I was thinking there is a draw somewhere, but it would have to be pretty large to kill the car. Maybe the regulator is not getting the signal to turn the alternator on?

If there was a draw, which I doubt, I think it could be a relay that I have in the trunk. It is a large blue relay that clicks like crazy when it gets vibrated, which is most of the time. I suspect that this is just a bad relay, and not the source of the problem.

Can somebody help with some step by step troubleshooting?

thanks a lot.

Fri Nov 21, 2008 11:22 am

I had the EXACT same problem in my 66'. What you have to do is start @ square 1 and work your way up. I started with testing the ignition switch, to the starter, to the generator (or alternator in your case), to the voltage regulator, to the battery. Turned out my regulator was bad which in turn was killing my battery over and over again. After replacing the battery a bunch of times, I finally decided to buy a volt test meter and just went over all of the wiring and tested it all to find out what the CAUSE of the problem is. To TRULY cure the problem, this is what you're going to have to do. Unless you want to replace EVERY part in the charging system.

Fri Nov 21, 2008 2:21 pm

+1 to the above.

And for a simpler place to start, disassemble your ground connections and clean them to bright metal, starting with the battery ground wire to body pan connection.

Sat Nov 22, 2008 5:33 pm

Read this thread. It may help...or not. LOL
http://www.thesamba.com/vw/forum/viewtopic.php?p=3407204&highlight=#3407204

Mon Nov 24, 2008 9:42 am

Guitarzan: Could you tell me where you got a replacement relay. I think the problem might be that relay. It clicks unmercifully. I haven't done a complete troubleshooting, but I definately want to start there.

Thanks.

Mon Nov 24, 2008 1:52 pm

Firts make sure that your relay is grounded through the mounting screw. However, I didn't replace the relay, but you can find them in the classified section.
http://www.thesamba.com/vw/classifieds/detail.php?id=634207
In the very last post, I stated that I discovered the dome light was the culprit. Once I removed it from the car, I no longer had a drain on the battery. Reference this diagram:
http://www.thesamba.com/vw/archives/info/wiring/bug_66_USA.jpg
Also, read this:
http://www.vw-resource.com/vw-resource.com_non_ssl/electrical_troubleshooting.html#drain
I also used this:
http://www.nls.net/MP/VOLKS/schem/drain.gif
If you discover that there is a drain, start by removing fuses one at a time and check to see if there is still a drain. If you remove a fuse and your volt/ohm meter shows "zero" then you know that the problem lies on that circuit. Then trace it from there by disconnecting everything on that circuit, one at a time of course. I hope this helps.

Mon Nov 24, 2008 1:56 pm

Oops, the relays I pointed you to are 6V. Just realized you have a 12 V system hence the 14.50 volts when running.
http://www.thesamba.com/vw/classifieds/search.php?...ton=Search