When my regulator went bad I noticed had no (none, zero, zip, all dark) instrument cluster test lights on when key was in position 2. My Bubba Diag was to recall a posting on eBay in which a seller noted this as a symptom of bad voltage regulator. I searched for completed items and found the post and completed my diag. New regulator and system is good now. (Old one was down to nothing on one side.) Then replaced the reg in my older W124 as a preventative measure. Both sides were down to nothing on that car. This is a 6 minute job.
1986 300E Anthracite + ECodes + MB Mileage Award