Illuminated door sill not working drivers side

[BasDust]

I have 2018 e class coupe, drivers door sill does not light up when opening the door. Passenger side is fine.
Anyone got any suggestions if its an easy fix? Merc Swindon says won't be covered under warranty, and could be any amount of time @£178 per hour to diagnose.
Or any suggestions for a decent indy in the Wiltshire area. Thanks.

 

[optimusprime]

Did no one tell you that Mercedes were expensive to run . Do the interior lights come on inside the car when you open the door ?.

 

[noogieman]

Perhaps the plasma display on your doorsill fried?

I have illuminated doorsills on all four sides.
I put an on/off switch in the boot to cut the power off, leaving doors ajar for a long time will eventually kill them