Opel Corsa Owner's Manual page 37

Keys, doors and windows 35
Overload
If the system is overloaded, the power
supply is automatically cut-off for a
short time. The system is protected by
fuses in the fuse box 3 194.
Initialising the sun roof
If the sunroof cannot be operated,
activate the electronics as follows:
with ignition on close the sunroof and
hold d depressed for at least
10 seconds.
Seek the assistance of a workshop to
have the cause of the fault remedied.