1991 190E 2.6, electrical surging
 

Hello gang, I have recently noticed that our Baby has developed a power surge, it goes along just fine and then dash lights fans, grow in intensity. It is a new alternator. I do have to reset the potentiometer, but must replace the meter as it is fubar.:D

Check the connections to the alternator and battery (don't forget ground wires and ground wire to body / engine!) - might also have the battery tested just to rule that out as a possible cause.

If no problems found with the above, take alternator back and get another.