Sounds normal to me. If you use the ABS often enough, it will be turned off as the battery falls below a preset voltage.

While driving, push up on three of your window switches at the same time, with the windows already all the way up. I bet that will dim your lights a little too.

Mike

__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E