Originally Posted by rshafferdc

On my 83 300SD, I believe I need to change the voltage regulator. My dash warning lights don't light up unless I tap on a very small metal retangular box on the rear/top of the alternator. That and the battery drains (battery warning light comes on very dimmly when engine is running).

I do clearly see the voltage regulator further down on the back of the alternator (brush internal type). But, I don't know what that small rectanglular box is (screwed down to the back of the alternator on one end and what looks like a wire coming off the other end....looping down the back of the alternator). Since tapping on this box changes what the warning cluster lights are doing (on/off)....I would assume that is the problem. But, other posts say similar cluster warning light issues = voltage regulator.

So, what is that retangular box and do I actaully need to take off the alternator to replace what I know is the voltage regulator?