XSeries-forum

Hi All
Just noticed that when the dashboard panel lights came on, the lights on both the instrument panel and the auxiliary control switches lights are flickering, has anyone come across this? Is the problem down to the switch control unit for the whole lights or is it a panel lights issue?
Can anyone point me to a fix to this problem?

Battery volts OK?

With the engine running?  My suspicion would be alternator regulator is uneven so the voltage is varying.

Alternatively (and if the engine isn’t running) does it change with the brightness setting of the display?  That might point at a different issue where the pulsed modulation circuit that drives the dimmer may be going faulty.  Not 100% certain, but that could be in the LCM (Lighting Control Module).

[quote="X5Sport"]
Battery volts OK?

With the engine running?  My suspicion would be alternator regulator is uneven so the voltage is varying.

Alternatively (and if the engine isn’t running) does it change with the brightness setting of the display?  That might point at a different issue where the pulsed modulation circuit that drives the dimmer may be going faulty.  Not 100% certain, but that could be in the LCM (Lighting Control Module).
[/quote]

If it were the alternator regulator would all external lights be pulsing/flickering as well??

That would depend upon the bulb type and pulse rate.  LEDs will pick it up faster certainly but filament lamps and HIDs have a different response time and may not show it.  It would change frequency with engine rpm though.

It’s one of the reasons why LED angel eyes pulse on the E53 at start up.  They illuminate in nanoseconds whereas filaments are in milliseconds (2 orders of magnitude slower).

LEDs are frequently dimmed by using Pulse Width Modulation which our eyes see as a dimmer/brighter light depending upon the pulse length.

I’m just thinking of possible causes, of which an alternator regulator is one.  Hard to check without a scope type display meter though.