W124 headlamp switch issue
 

Earlier today I removed the headlamp knob to clean it and I put it back on. Later on at night I turned it to headlamps on and pulled it out to put the fogs on and it didnt lock to the on position. It just snapped back to off.

whats wrong?

hello?

Did the fog light just snap back to off (like it was pushed forward), or did the knob rotate to off?

Does the knob hold well on the switch or does it feel loose?

yes, it just snaps back forward. It doesnt lock to the on position.

The switch is hard to turn. I cant even turn it to the left or right parking light positions even though when I removed the knob everything was centered.

I think this function is in the switch assembly.

You can take the knob off while in position 1 (park lights) and try to pull it with pliers (covered with a thick rag so it won't gouge anything). See if you can observe anything unusual from outside. Otherwise, this sounds like an internal problem to me.

Not that well versed with these mechanisms though, just giving you an idea of what could be wrong.

I forgot - is this cabriolet a Canadian version? Or maybe I'm confusing it with another vehicle. I know in Canada, and the reason I ask, is they're required to have DRL's. So not sure if this affects the switch.

My switch eventually completely broke last year. It was increasingly difficult to rotate for a few months and I could hear the insides making noise when I rotated it. When I finally replaced it, I took the old switch apart and found that the ceramic housing inside the switch had deteriorated and the pieces had become wedged between the rotating parts. If you shake your switch and hear noise inside that sounds like a set of maracas, that's probably what it is. The switch itself is an engineering masterpiece. I was impressed. I think it cost about $50 for a new one.

Bingo!

If everything was fine before you removed the knob, I'll bet you installed it indexed incorrectly.

What you thought was the "off" position was actually the left all night park position... Two click clockwise would not be "headlamps on", instead would be the true "off" position, and the stem would by design return to fog off position.

Jim

I will try and rotate it without the knob and go from there.

well, finally got around to checking this issue out.

Removed knob and bulb and used pliers to move the stalk. It would not turn any further counter clockwise than with the knob on. Then moving it to headlamps on and pulling out, still not locking for the fogs or rear fogs.

Guess I need a new switch.

There's a ball bearing on a spring inside that does the detents. The switch is kind of a pain to open up though, I'd want another on hand before taking the one on the car now apart. Good new is they were used on lots of cars so finding a good used spare shouldn't be too bad.

-J