19V at the Battery
 

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.