Faulty Voltage Regulator? Get Help Now!

Hello everyone.

I'm having problems with my Golf3 TDI, manufactured in 1997, with an 81kW (AFN) engine.
Board voltage. If, after starting the engine, the glow plug relay fails...
When the vehicle is switched off, the low beam headlights (as well as the dashboard lighting, etc.) will remain on for a short period.
(~20ms) a noticeable improvement. When the glow plugs are switched off.
It's also present in the coolant. Is this normal, or could there be a problem with the voltage regulator?
I experience particularly persistent problems when I drive at a constant speed of approximately 2500 RPM during the afterglow phase.
because that's where the relay cuts off the glow plugs, and apparently at 2499 RPM.
Anyway, the relay starts to flutter intensely there, and my low beam headlight...
It then looks more like a high beam assist! Why didn't VW do that?
Is a hysteresis built in, or is there one that is defective in my case?
What can I do? Where can I look?

I'm grateful for any advice, as my consumption of light bulbs is increasing.
has now reached unimaginable proportions...

Best, Olli.

How about measuring the voltage?
No one will be able to help you like that...

Oh yes, I had forgotten to include those details.

Battery voltage:
Engine off: 12.4V
Motor on: 14.4V
Full throttle: 14.6V.

When the glow plugs are switched off, the oscilloscope shows a voltage spike of just under 18V.
for approximately 20 milliseconds.

Hello Eum 76...

How long after turning off the engine did you measure the battery voltage?

Best, Steve.

Hello EUM 76.

You write:
Battery voltage:
Engine off: 12.4V
Motor on: 14.4V
Full throttle: 14.6V.

Voltage is approximately 1 volt too high.
ev. LIMA Problem.

Best regards,
Michael

Eum76 wrote:

Voltage at the control panel (measured across the battery): Engine off: 12.4V Motor on: 14.4V Full throttle: 14.6V

I would still consider that to be normal.

Quote:

When the glow plugs are switched off, the oscilloscope shows a voltage spike of approximately 18 V for about 20 ms.

Hmm, in my opinion, shouldn't the battery "absorb" such voltage spikes?

Did you actually measure that directly at the battery, or somewhere else in the vehicle's electrical system?
If that's the case, there might be a resistance or loose connection somewhere in the charging cable (or even the ground!) between the alternator (LiMa) and the battery.

Hi,

Your voltage readings are perfectly normal - they are almost identical to what I see on my ASV.

Do you have electric windows? If so, does it create the same effect if you let them roll down against the wind?

Best regards,

Jan.