Low beam indicator blinking and turning off any other light

[Klinto75m]

First a little information about the car:

• Model: 406 2.0 HDi (RHR)

• Year: late 2002

• Full mux

I've been having trouble with the lights ever since I bought the car about 2.5 years ago. I think it's something with the light sensor, but can't pinpoint anything specific. At random intervals, the low beam indicator (left green lamp) will start to blink for any amount of time. Haven't yet found a pattern in the blinking or when it starts. Seems to be completely random both in broad daylight and at nighttime.

If the high beam or any foglights are on when the indicator starts to blink, it'll automatically turn it off.

I've gone through 3 COM2000 thinking it was the problem, but have had the same experience with them all (they were all used).
The only setting I've messed with regarding light is enabling DRL in P2000 since it's required by law in Denmark.
I've installed aftermarket side indicators, but don't think it's related.
No related errors are showing in P2000 when running diagnostics (have a few relating A/C etc.)

Link to video of the indicator blinking:
https://www.youtube.com/shorts/dL_h-ZPPwek

When it happens, I can stop the blinking by pressing the end of the left stalk. Not sure what it does, but have heard something about automatic lights.
And then it'll randomly start blinking at another time.

Any help is greatly appreciated, as this is one of the last kinks I need to work out.

[GingerMagic]

Have you disabled the auto lights using PP2000 too?

I once enabled the DRL but it messed around with the lights, disabling auto lights fixed it. Using the button on the end of the lights stalk will turn on/off auto lights but occasionally the car would turn them back on again just to upset me so I disabled it completely - I win

You can also use the DRL on/ auto lights off setting to bypass a dodgy Comms unit.

Give this a go first.

[Klinto75m]

I remember vaguely disabling it. But I'll have an extra look in the weekend. Appreciate the answer

[GingerMagic]

I think you can also use the Customer Options menu to mark the auto lights as absent - it's been a few years since I've dabbled with it ....

[Klinto75m]

I've checked it today, and the automatic lights are disabled. But it's been the first time, where I could see an error on the com2000 unit. "Periodic fault: lighting control not coherent". I know this points to the com2000 being faulty, but going through 3 with the same fault, seems very unlucky

[GingerMagic]

There is a common fault with the Comms unit - where the tiny metal ring inside the light stalk gets worn out.

If you still have one of your old Comms units you could give the repair a go

There are a few videos on YouTube if you search for Comms unit repair