Electrical problem with '85 300SD
 

There is a sort of terminal strip on the right inner fender to which harness for the positive battery cable and for the alternator connect. It bears P/N 126 540 0069. Is this merely a barrier strip, or does it contain other critical components inside? The screws that attach the various leads are severely corroded, and I've managed to strip the head of one of them in an attempt to remove.

Can anyone shed some light on this?