This for a W123, but the w124 is almost identical. this is a Rheostat Rebuild in the DIY resources.
This will give you an idea what it looks like.
PeachPartsWiki: Dash Light Rheostat Rebuild

I have seen the Rheostat`s with a jumper wire soldered on the back and I have seen them remover and a wire soldered to some female pins and pushed on the 2 contact pins the stat sits on.

new one`s are close to $100 as I remember, I see good one`s in PNP all the time. mine workd good and seems bright enough, and some nights when Iam tired, I can at least turn them down.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works