Driver side electronics fail

Moin municipality, maybe someone already had this error: With my V50 D5, MJ 06 the electronics of the driver side is dropped. That means, the doors on the left do not close to key command, window lifter and mirror adjustment does not work. If one sets the ignition more often and then it works again for a certain time. Regularities or a reproducibility I have not yet been able to discover. Any Ideas, except the drive to the – greetings