how to replace light bulb in headlight switch 1977 450 sl
 

How to get to rear of headlight switch, instrument panel (for 1977 450sl) or lower panel (under steering wheel). Advice appreciated. Abe G

Boy, I didn't think 107's had any illumination for the headlight switch, maybe the small center one to let you know your foglights are on.
Gilly

You just need to pull the knob straight out from the front to reveal the socket for the light bulb. It takes some effort to get it to pop off, and to do it without damaging the knob.

The bulb is a 2.1 watt bulb, Sylvania #2721.

I'm not 100% sure that the bulb actually is wired up on that switch, however. I've replaced it on both the original switch that was in my 1980 450SLC and then another replacement switch I have just put in and the bulb has never iluminated when the fog lights are on.

Steve

bulb replacement on headlight switch
 

Dear Steve: When you remove the switch (knob) there is no place for a bulb, just washer. It appears that the bulb may be in the rear of the switch, behind panel. Schematic on m/b micro diagram shows bulb (obtained same), but how to get at rear, either instrumnet panel or lower panel, or maybe no bulb at all ? Any advice appreciated, and thanks again. Abe G

You might very well have a switch that does not have a bulb socket.

Attached is a picture of the switch assembly, a real jigsaw puzzle to replace the wires.....

The bulb socket is the plastic section at the top of the switch.

As I mentioned I'm a little dubious that it actually works in our older cars.
I could just have the wrong bulb in there, but it seems to make good contact, and it's the same bulb used in many other places in the interior.

As you can see there's no way to get to any bulbs from behind. That "inner" set of connectors is covered by a plastic cover, I suppose to prevent accidental contact with anything from the "outer" set.

Steve

bulb (if any) in headlight swich
 

Dear Steve: Thanks again for your prompt and accurate info! When my switch knob pulled, there is no provision for a bulb holder! So probably nothing on rear? Guess I'll just live with what I have. Regards, Abe G

Abe,

Try removing your instrument cluster to access the back of the switch. I remove my cluster from time to time and it is a very easy job. With the cluster out it is easy to get to everything in that area of the dash.

Of four benzs I've owned, only the 85 190E had that little orange light in the center of the light switch knob for fogs. I looked for it in my 80 450SL, but none, same with my 84 and 87 300d, none also! It must have been optional?

Headlight Switch Bulb
 

I have an 87 560SL and the light (if any) doesn't work either. I also have a 94 E320 and it does have the light and it works. I thought I just had a bulb out as well. It's nice to know I may not even have one to worry about.

My '79 300SD has one that doesn't light up either even with a new bulb...