The device in question is called a DIMMER, a POTENTIOMETER, or a RHEOSTAT. By definition:

- A dimmer is a device used to vary the intensity of an electric light.

- A potentiometer is a 3-terminal resistor with an adjustable center terminal; used to adjust voltages.

- A rheostat is a continuously variable electrical resistor used to regulate current.

I prefer the term "RHEOSTAT" because it accurately describes both the operation and function of this device.



Whenever you have a problem such as intermittent or dim lighting with an instrument cluster illumination, this device should always be the FIRST THING to look at, especially on W126, W123 and W116 (and other older chassis). I did the same thing on my diesels, just like dieseldiehard.

Eric