What is this light on my dash?
 

I have an amber light to the right of the fan speed selector on the dash and a knob (Twist On / Off rheostat with about 270 degrees of rotation) on the left side of the HVAC control panel on the dash. When I turn it on I hear a hissing behind the dash but have no Idea what this thing does. Any Ideas?

It could be the alarm.

Dude, is that your pimpin cell phone? That's hot.

What's the other arrow pointing at?

The other arrow is pointing to the location of the knob that controls the light. Its on the side panel where your right knee would rest on the dash. Also, thats not a pic of my car. I borrowed that pic from google to show where the light is.

The hissing sound makes me wonder if your switch isn't some sort of manual air recirculation switch. Take out the glovebox, and see if the activation of said switch make the recirc flaps move. If they don't move, look and see what does.

The flaps don't move. The knob has the MB insignia on it. It has me stumped.

Ejection seat ...

I doubt its an ejection seat, however handy that would be. I'm wondering if its some sort of traction control or shift control.

maybe shift control, but traction control on a 190?

Nitrous switch?
Afterburners?

air recirc switch
 

The manual air recirculation switch is the rocker switch oriented horizontal on the left side of the blower slider switch. That light is aftermarket as far as I can say compared to my 1984 190D.

Happy Holidays

Kevin
1979 240D manual
1984 190D manual

Twist On / Off rheostat with about 270 degrees of rotation=
Your temp control switch.
Supposed to be half blue(cold) half red(warm/hot)
with #s on it.

amber light= Aftermarket doodat, maybe alarm.
When does it come on, if it does at all?
Does the car have foglights, front or rear?
Does it come on when you turn your heat/ac on?

A little more info would help.

Louis.

The knob is on the side of the console where your right knee would rest in the driving postion. The light comes on with the knob. Once the light is on there is a hissing behind the dash. The "half blue" knob you speak of is on the dash facing the back seat while the knob in question is located on the left side of the console facing the drivers door panel. It acts like a power/volume knob, twist to turn on (amber light comes on), then rotates to the right with an indentation about 3/4's of the turn, then continues to turn till it stops. There is a MB insignia in the center of the knob.

Gas neutralizer from obnoxious passengers after having lunch at Taco Bell