w211 small black button ???

[camerafodder]

I have bought the car 5 years ago and today saw this .

OK, so how is that relevant to my (what I thought) was a helpful suggestion based on your question of just yesterday?

 

[PobodY]

Probably not connected to anything any more. - I've got a little momentary switch in the Nissan which I think was originally connected to the alarm for valet mode and programming new remotes.... but it is just a switch plugging a hole it would leave if I removed it now.

 

[MikeInWimbledon]

This Engineering checklist may help

 

[mersum1es]

I have bought the car 5 years ago and today saw this .

Is it old taxi, I thought it might be alarm button of taxi equipment, dunno are UK taxis using such system.

Then aftermarket eberspächer heater on/off switch looks bit like that (there is a light inside of button), but why disassemble heater system and leave switch behind...

mystery!

 

[4life211]

OK, so how is that relevant to my (what I thought) was a helpful suggestion based on your question of just yesterday?

It doesn't disable ignition or I don't know how it works.

 

[whitenemesis]

5 years and you have only now discovered this button...??

 

[QUTSELL]

My guess is its a giggling pin,that is connected to the laughing shaft.