Driver's side courtesy light no worky

[Tyre Tread]

I noticed a little while ago that the light courtesy light didn't come on when I opened the drivers's  door but hadn't noticed until last night that the sill light and other courtesy functions also are not operated by the drivers's door. When a passenger got into the car in the dark the cabin lit up like it should (including driver's side sill light.

I had also been irritated the recently the doors were locking and alarm resetting after I got into the car (driver's side) and it was only last night that I connected the two.

Clearly the car isn't sensing the door driver's being opened. 

I've done a search but not found much info except to say it is likely to be either a fuse or the control bos but I don't know which fuse or where it may be located or which control box and whether it is fixable.

Can anyone with experience of solving this problem help me please?

[Herbie]

Unlikely to be a fuse because if it was then the lights wouldn't work when the passenger door was opened.

There's usually only two or three locations for fuse boxes - engine bay, passenger's and/or driver's footwell - and the fuse box lids usually have fuse number and circuit description on them.

Most likely culprit in this case is the door switch, which is often a plunger that moves in and out as the door is opened/closed. You may find that the plunger has seized.

[Beamish]

 

+ 1 on the door switch. Try getting some WD40 or Contact Cleaner into the switch and give it a good workout with your thumb.

[Tyre Tread]

I was about to pooh pooh your suggestions gents BUT I decided to investigate and played with switch and it worked intermittently.

Took switch off (Not as easy as it sounds as there's zero spare play in the wiring loom so had to use some ingenuity to stop the cable & connector disappearing into the B pillar) and checked it on the meter and sure enough it was intermittent.

Sprayed it with switch cleaner- still intermittent.

Nicked the one off the back door and put it on the driver's door 😁 (for now)

So apologies and thank you for making me check the obvious.

Occam's razor strikes again.