Battery went flat -- just like that!

...did you actually test battery with meter? Could it be either the groud connection or the battery connection to starter is loose, thus not providing a path for current to flow regardless of state of charge? ...just throwing a few things out....you say you are an EE....well grab ur meter and start hunting =-))

...Gareth

......................I can't believe that the battery went so dead that the radio lost its memory and then was OK after driving home. Also, I think that it's true that an alternator won't have any output (unlike a generator) if there's no connection to a battery in the system or if the battery is totally dead. The solenoid click indicates that there should have been enough current to prevent the radio from losing its memory. Maybe there's something going on with the radio that's unrelated to the starter failing to turn over for you at that store. I don't know whether it's true for a '71 baywindow but I do know that the later generation vanagons have no headlights when the engine isn't running. I'm still as much puzzled as you as to what happened though. I'd make sure that this new battery isn't defective (internal break in continuity?) and I'd also check the ground strap connection from the battery to the chassis and also the ground strap between the tranny and the chassis. Another possibility is that the ignition switch has started going bad which could have caused reduced amperage going to the solenoid (a common problem). Being an electrical engineer, you probably wouldn't have too much trouble figuring out how to put in a relay from the ignition switch which could provide a much stronger connection from the battery to the solenoid. If you don't find anything wrong, I'd wait and see if it happens again but I suspect that a relay or new ignition switch will ultimately be the answer for you.

.......hope this helps

Nah -- I was in a multimeter-free zone when the incident happened. I've pitched one aboard and when it happens again I'll do ye basic poking around. If this is not a Known Issue then I'll sort it out.

Mike RJS Elliott

I know. All the station presets were gone.

Well, I turned the key twice and got a click both times. I wandered off to find my wife (nearby in another car) and asked her to pop over when she could to help me push the thing into the downhill position. I tried the key one more time while I was waiting for her and this time there was not enough juice to pull in the solenoid. It could have been this moment when the voltage dipped enough to wipe the radio memory.

Next time I'll have my multimeter handy.

Uh -- you might be right about that. But still, not even a solenoid click the third time.

This battery was put in because the auction house had the same problem

-- flat battery -- with the original one. So they dropped in this one. Two in a row with the same symptoms is less likely than a bad guess about the cause of the problem.

Good thinking.

Ah -- very, very useful bit o' information, that.

My copy of the Bentley manual came this afternoon. I'll noodle through the wiring diagram. Anyone have any idea how much current the solenoid draws? What the relay contacts should be rated for?

Very helpful! Thank you.

Mike RJS Elliott

Use a common Bosch automotive relay. Here's the scheme (from Glenn's site):

Speedy Jim

Saaaay . . . that *was* speedy, Jim! Thanks for the tip! I think that even I, with my high-priced engineering degree, could figure out how to mount and wire up that thing without causing too much damage that a real mechanic would have to later set straight (he said, not noticing the plume of smoke coming off the wiring harness).

Tyhat's Why they call him...................Quick James

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Solenoid draws 30-35 amps to pull in and 12 amps to hold.

Not sure about busses, but Beetles have adjustable speedo lights. Turn the head light switch in the dash clockwise to see, if it helps.

Excellent suggestion -- I already tried that but neglected to mention it. I'm going to wrench my back and poke around under the dash and see what's up.

...does it dim normally if dimly? I'd check ground....if it doesn't dim then I'd look at the switch, and specifically the wiper on the potentio...

..Gareth

Speaking of dim bulbs -- here's a newbie dimbulb question: where's a good source for bits like replacement headlamp switches and suchlike?

And the "special tool" required to remove the escutcheon (locknut) that holds switches onto the dashboard, where can that thing be purchased? (per Electrical System, page 7, Bentley's Official Service Manual for buses 1968 - 1979.)

But, thanks, everyone -- you answered my question: it is *not* normal for the speedo and instrument lamps to be that dim. Didn't know if it was a VW "feature" or not.

...any VW specific parts retailer will carry these. On my personal vehicles these always get replaced with used parts =-))) Usually takes two or three pulls to find one in good shape though...

....a large pair of circlip pliers or needle nose will work. But if you find a source for the tool and its cheap that would be good informationm....I have seen it *somewhere* ...hmmm...

..Gareth