The 1994 & later C-class(US models) use a computer to operate the sunroof & it is powered-up all of the time part number is 202-820-09-26.
The only time this should operate the sunroof is when locking doors(or unlocking) OR if you operate the switch.
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)