Funky Interior Lighting Issues

[jlneonhug]

Hello, long time stalker and owner of W203 for about 12 yrs.

Have an issue with the interior lighting;
- At unlock the lights work, as you open the front door all light go off, if open rears the rears on but fronts off
- when driving the orange ambient lighting flickers like it's a bad earth, the interior light also flickers faintly, when pressing the side interior or main to come on, neither works
- As you off the ignition after a drive the interior lights come on as per perfectly but switches off straight away as door opens.

I have a Launch code reader but I don't think it reads all of Mercedes codes, only brakes emissions, tcs etc. Attempt a clear anyway but no change.

A side topic, the heater thermostat in car has been weird, only does mildly hot but does not change to temp, only when clicked to max cold and it will blast cold. Maybe related maybe not?

Charged and reconditioned the battery so I don't think it's a battery issue...
Fuses checked.

I've taken apart the turbo on this and replaced the actuation plastic screw within the ecu unit before (with the help of guides on here, thank you forum!) I don't want some interior lights defeating me, ha. Any clues to look would be most helpful.

Thoughts most welcomed, thank you!

 

[jlneonhug]

Some update and more info.

If I flick it onto sidelights I can replicate the flickering from the interior light, it looks like a short or bad earth.
I've changed the 501 sidelights at the front with some osrams (both), but that hasn't helped.
I've wiggled the connections /cables near the sidelights but no change.

Is there a relay or comms module between sidelights and interior lights?