Hey there folks. My ML430 did the dreaded dashboard idiot light freakout this weekend. I replaced the brake switch this afternoon with no luck.
My symptoms, BAS, Air Bag, ETS, EBrake lights all on. As soon as I rev the engine to anything more then idle, AC cuts off and windows will not operate. Since it seemed to happen on revving, I decided to check the V+ at the battery. At idle it is 13.5V. As soon as the engine is rev'd past 1500 rpm the V+ goes to 18.7 V. If this were my old 914 I would replace the regulator and then the battery since clearly it was over charged. Since this is not my old 914, can someone please give me a clue... is the VR integrated into the alternator? Should I order one from World Pac right away or should I get the Alt tested.
Any and all help is greatly appreciated so my wife can go back to driving her ML and give me back my car

Oh yeah, 1999 ML430.

Most likely the voltage regulator.

You can replace that w/o buying a complete alternator.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator