Unknown Intermittent Dash Light
 

What is this dang light? 1981 - 240d.

I don't know, that spot is unused on my 83. Is there any kind of symbol?

Nope, that's kind of a problem. What you see in the pic is how it's displayed.

Do all the other lights work when you turn on the key? Maybe someone put a bulb in the wrong place.

That's a good point. That thought hadn't crossed my mind. I'll pull the assembly out and take a peak I guess.

My guess is the seat belt warning bulb is in the wrong socket.
Somebody might have installed an afterglow system for the glow plugs and wired up that space as an indicator that the system was on...

If it's intermittent, I would guess it might be a misplaced brake pad warning light.

i am leaning toward that aswell,it obviously appears the car was in bright sun when the picture was taken,so no need to worry about a loose connection to a bulb,causing the exterior light out bulb to come on.

W123s don't have a lamp monitor. I have seen cars where the seatbelt light (and buzzer) will go off at random due to bad grounds, though.

-J

speaking of seat belt warning indicator,my 124 is supposed to have lights that light up overhead where the moon roof switch is and dome light operates,i believe,what would cause the lights not to light up,also when i open the door the interior light does not operate,but i can manually switch the dome light and reading light on and off,does anyone have any ideas what controls the seat belt warning lights up there?

That means either your driver's door switch is bad, or one of the entry lights shorted out and broke your buzzer relay. It's not hard to fix though, I posted how to in other threads.

-J

If it really is the pad sensorm you'd notice it primarily when stepping on the brake pedal.
The bulb harnesses have a numbered strip on them which corelates to a number next to the holes in the back of the cluster that the sockets fit in to.
Gilly