While changing my thermostat on the 87 300dt, the thermostat housing dropped on top of the alternator and caused that small wire on the back of the alt. to fry as well as smoke from the battery. I suspect that wire is some kind of current limit fuse. (I wish they had put that thermostat up by the radiator). It appears to be the orginal TS probably because its so difficult to access. Anyway, is that wire that fried and dropped off necessary? Rectifiers zapped? Thanks for any comments.
Oily

Are you sure the smoke was from the battery?? Not likely - There are 3 wires which go to the connecotr on my alternator, terminarting in a plug on the back of the alternator. There is one other wire on the back of the alternator, the suppressor capacitor. This is the only light gauge wire on the alternator that I am aware of.The fusible links, where fitted, are normally located close to the battery, so that they protect the wiring.
BTW, my comments relate to the OM617 engine with the Bosch Alternator, and the fusible links are from my experience with Japanese cars.