Tachometer Lights Dim? Golf IV Dashboard Repair

Guest Free account, no CAN development support

Hello there!

I've noticed that the illumination on my Golf's dashboard isn't as bright as on newer 4-series Golfs

! The knob for adjusting the brightness on the instrument panel is turned all the way up, and it can be adjusted normally, but it still only gets dim!
Can someone tell me something about this, or hopefully help me?

Thank you in advance!

Translated on 01-09-2026, 2:15.

Please check the voltage after the brightness control.

Guest Free account, no CAN development support

What should it normally be?

Translated on 01-09-2026, 2:16.

I'm not familiar with the wiring of the Golf 4, but if there's a potentiometer in the circuit, it should theoretically range from approximately 12 to a maximum of 14 volts.

There might be more to it than that, though.
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Translated on 01-09-2026, 2:17.

"As far as I can tell from my Polo, there's nothing better than a traditional potentiometer and voltage drop. It looks more like something that's pulse-width modulated. And then, using a regular multimeter to measure the output voltage won't work. I suspect that the G4 uses a similar technology, because otherwise, LEDs can only be dimmed in a rather uneven way."
Best regards,
pretzel