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lights flickering

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Nellis

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Apr 2, 2009, 12:50:28 PM4/2/09
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I have a '74 Super, and I am having problems with the headlights, and
dash lights, flickering, occasionally. It does not happen all the time,
but when the lights flicker, the generator light comes on, and the
headlights and the generator lights are very bright, and the flickering
is at a constant rate. There does not seem to be any particular event
that occurs to start, or stop, the flickering. Once the flickering
starts, it may stop in a couple seconds, or last until the car is turned
off.

I am looking for suggestions on what I should look for.

Speedy Jim

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Apr 2, 2009, 4:26:04 PM4/2/09
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US '74 Supers had an alternator.
Does your engine have the original alternator
or has a generator been substituted, or even
a later alternator?

First step, I would connect a multimeter across
the battery posts so you can monitor the charging
voltage as you drive.

Normally, it would sit rock-solid at something
like 14V (range of 13.5 to 14.5V. If it goes above
14.5V when the lights brighten, the regulator
is not working correctly, for whatever reason.

Try to find out just what charging system is installed.

Speedy Jim
http://www.nls.net/mp/volks/

Hal

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Apr 2, 2009, 11:35:16 PM4/2/09
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> I have a '74 Super, and I am having problems with the headlights, and
> dash lights, flickering, occasionally. It does not happen all the time,
> but when the lights flicker, the generator light comes on, and the

Are you still running the 4 wire Motorola alternator(two connections,
one has 3 wires and the B+ lead) or has it been converted to a single-
wire internally regulated alternator(one wire, usually a spade
connector and the B+ connection with a ring connector)?

Chris

Jim...@msn.com

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Apr 7, 2009, 9:56:34 AM4/7/09
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Check the brown negative ground wires. Maybe it has a loose or bad
connection.
Check where the brown wires connect in front of the gas tank.
These links might help:

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

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

http://www.vw-resource.com/generator.html#charging

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Nellis

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Apr 7, 2009, 10:19:05 AM4/7/09
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The alternator is the two-post Bosch AL82N. Not sure how old that is.
I will check the voltage across the battery tonight. The only problem
that I have now is that for some reason the headlights are no longer
working. It could very well be a ground wire. I will check those
connections as well.

Thanks.

Speedy Jim

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Apr 7, 2009, 11:51:19 AM4/7/09
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If both side headlights quit at the same time, it's more likely
something common to both, such as the dimmer relay or the
Ignition switch.

This page of my web site:
http://www.nls.net/mp/volks/htm/elec.htm
Look for: "Headlight Dimmer Relay circuit '71 thru '79."
Has a simplified diagram.

Speedy Jim
http://www.nls.net/mp/volks/

Nellis

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Jun 27, 2009, 5:11:20 PM6/27/09
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Jim and Hal,

Thank you both very much for your comments.
I wanted to let you know what I found:

1. The problem that I was having with the headlights not working turned out
to be a faulty headlight/dimmer switch. After replacing that, I was back to
the original problem.

2. Now that the problem was occurring again, I ran the voltage test across
the battery. While idling, the volt meter read about 14-14.5volts. When
the lights got brighter, the voltmeter read 20v. So, the problem is
probably the voltage regulator. After some searching, it appears that the
voltage regulator is missing - hence the problem.

I am ordering a voltage regulator now, and we should be all set.
Thanks again for all your help.

- Nellis


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