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What can kill a voltage regulator?

Ok, I got a '67 bug and my generator light came on. Both the generator and regulator were new (the whole car was restored from the ground up...just got it out the shop 3-months ago...and although both gen & reg were built new (not rebuilt) by BOSCH, they were built in Mexico, so...

Anyway, I checked the generator max voltage (ground the DF, disconnect the D+ and measure the voltage from that to ground) and got .4V to .

8V, so it looks like the generator is gone. Funny thing is, ever since I got the car out the shop, the reading on my voltmeter (VDO) has been up and down -- pegging out at 16V on the highway, but dropping to 11V at idle...down in the red. Just before it died it was down to 10V at idle (minumum for this gauge is 8V). So I think the regulator burned out the generator. I guess I should have paid more attention to it, but I'm still getting use to the quarks of this bug (I had a '68 for 23-years, but that's another story).

So I ordered a new gen & reg, but I'm wondering if there is anything that could have caused the regulator to malfunction? I'm thinking this thing is like a fuse: it shouldn't just blow for no reason, right? But then again, it is made in Mexico, and it uses solid state parts and you can't crack this thing open and look for burns like the old ones.

Assuming the new stuff I get is good, should I worry about anything? Something outside the generator-regulator system that could damage either?

Ken H

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Ken H
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I have tried one of those Bosch solid state volt regs with success on a '71 Bug. Well until a piece of metal fell on it shorting it out. lol I suggest always having a back seat in place! ;-) I prefer the one with contacts in it! Sounds like yours was malfuctioning from the beginning! 16V is too high! I usually polarize the generator and suggest you do that to your current one before replacing it. It is a good way to see if it still works too!

JMHO

Reply to
One out of many Daves

Yea, I didn't install the last one, but I'm sure they did it right. I think you're correct, this thing was never working right from the start. I have one of the old regulators. It looked like crap on the outside but I openned it up and it was down right pristine. No burn marks or broken wires. I think I'll carry it as a spare.

Ken H

Reply to
Ken H

The late style VRs have the whole upper body hot (either D+ or B+, I don't remember) so you have to be careful that they can't short to anything.

The full fielding test you did was a reasonable thing to do, assuming you also removed the DF wire when you did the test. (If you didn't remove that wire, then you probably fried the VR during the test.) If it won't go above 14 V, then there's something wrong with the generator.

You should also put the battery on a trickle charger for a few days and verify that it's okay. It should slowly rise to above 13 V, although this can take quite long if the trickle is small and the battery is discharged.

The symptoms you started out with COULD also be due to a bad battery, but it's clear that you have other bad parts by now.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

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