minor electrical niggles

[afterglow]

Hi.....i have some minor electrical niggles on my w210,wondered if anybody could give some insight into?

1: The passenger sidelight went the other day. Lamp defective warning came up on dash.
Have checked the bulb, but seems to be ok.
The previous owner told me, he had some problems with that too but said it was a fuse.
So, obviously shorting out somewhere, as it keeps on doing it. All fuses are ok. Have checked in all 3 fuse locations.
Any ideas?

And 2: The drivers underdoor light comes on by itself occasionally. This happened to me on the motorway, so smooth road, no bumps etc.

3: the centre dash, central locking switch doesnt work.

Apart from that, all my electrics are spot on!!...but just wanted to see if anybody could help me with solving these 3 niggles

 

[alibally]

Hello. The headlamps on the W210 may have a resister built into the internal headlamp wiring loom. If you look inside the headlamp and follow the bulb holder wiring there could be a little lump in the wiring. this can burn out causing he bulb not to work. Its to reduce the voltage slightly at the bulb.
The second and third fault could be linked. Does the interior light work ok? The door pin switches are really sensitive and if the door is even slighty badly adjusted they can cause the switch to open and close when driving up the road.

 

[afterglow]

Many thanks Ali....sounds like a good explanation to my sidelight problem. Need to take my headlight off to sand the lens anyway, so will investigate properly then i think.
IF it is the problem, then i guess id need a new loom? Is it a job i could do myself? Or best left to an expert?
The other problems, yes the interior lights all work fine. Just noticed when i was driving at night the light coming on sometimes on the door. Just the lower door light thats all. Will try and look into that door pin aswell.
Thanks for your help

 

[afterglow]

Just wanted to add, when i press the central locking dash switch, with engine off, it still doesnt work but i can hear noises from the passenger door. Vacuum pump im guessing. Basically sounds like it should work, only locks dont go up or down!

 

[afterglow]

Welll, ive traced the central locking dash button problem. Appears to be a leak in the vacuum hose in the passenger door where the door lock is.
Not quite sure how i can fix it, access looks very limited, but at least i know the cause!
As for the door underlight, the door switch is cracked, ordered a new one,. so hopefully that will fix it!