Sounds like the over-voltage relay is taking a nap every once in a while. It is the power supply for the computers that operate these items.

------------------
MERCEDES BENZ MASTER GUILD TECHNICIAN (6 TIMES)
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
190E 2.3 ITS RACECAR
1986 190E 16V