w203 problem with rear fog lights

[madbonky]

Wonder if anyone can help, on the rear light clusters the bottom lights carry double fillament bulbs, one fillament being the rear light when headlights are on and the other smaller, brighter fillament being the one which activates when rear fog lights are switched on.
Problem is when the lights are switched on the fog light fillaments come on even though i have not switched the fog lights on, so it looks like i am driving around with rear fog lights on all the time, i have taken the bulbs out and cleaned/checked teminals but with no success, probably explains why the old bulbs both burn out i guess....

 

[nigel cross]

What year is it, sounds like a facelife version, as on the earlier models only one rear fog lamp came on, which was on the offside.

 

[BlackC55]

If the one and only fog lamp is on all the time I suspect a possible rear SAM or light switch issue.

 

[madbonky]

hi there,

the car is a 52 reg so face lift model, fog lights are on both sides, it did work ok when i first replaced the bulbs but now the fog light fillament is on all the time when lights switched on, switching the fog light switch makes no difference, the lights just stay on.

 

[Alex Crow]

As above, you only have 1x rear fog lamp (driver's side) not 2x.

I suspect a confusion of bulbs here, do you have 2x contacts in these sockets that you are fitting double filament bulbs to??

Also note that when swapping bilbs around or replacing them you have to turn everything off and on again (including ignition) to reset the system...

 

[clever dicky]

hi there,

the car is a 52 reg so face lift model, fog lights are on both sides, it did work ok when i first replaced the bulbs but now the fog light fillament is on all the time when lights switched on, switching the fog light switch makes no difference, the lights just stay on.

W203 face lift came in around early 54 reg.

He might have squeezed the brake / side light round the wrong way?

 

[madbonky]

rear fogs always on

Both the bottom bulbs on both sides are dual fillament as these are 2 connectors on the light cluster bases, all the other bulbs have only 1 connector so will all be single fillament, the fog light is on both sides when on, the top lights are the brake lights and the bottom lights carry the night side lights on one fillament and the other fillament is the fog light, the 54 face lift only carried minor revisions i belive the rear light set up on the estate which is what i have stayed the same, unless anyone know different?
I have cleaned connectors, un plugged the rear clusters, changed the bulbs with ignition off etc, any ideas?