Hi Jfreezn,
I to have suspected an electrical connection problem on my 2000 ML 320.
My question to you or anyone else with ABS unit is:
should the electric motor that is connected to ABS unit be running when engine is started.

Can someone with same vehicle check to see if motor is running by starting
engine and carefully placing your hand on electric motor to detect motor running or not.====PLEASE ONLY TRY THIS IF YOUR CONFIDENT AND WILL NOT CAUSE INJURY TO YOUR SELF.

Thank You