Door locking/alarm problem

[Ed Addis]

Golf 1.9TDI 100 BHP 2003 - aftermarket alarm.

There are a set of interdependent and intermittent problems. The basic problem is that the remote locking and alarming mechanism malfunctions. The drivers door doesn't always lock with the remote, and new today, the central locking of all doors is not working. Also, the alarm is not arming - not red pilot light. Sometimes when the remote is used, three beeps inside the car can be heard outside. Today the car can only be locked with the key and only the driver's door locks and unlocks - ie alarm/central locking is dead. Any ideas? Replace ECU?

[Ed Addis]

Further investigation - the guy who services our cars has carried out tests and believes that it's the comfort control unit that's faulty. The part no is 1CO 959 799. I've seen this also referenced as 1C0 959 799 - is this the same unit? Spoke with local VW dealer parts dept and they looked it up and told me there should be 01Z at the end of the part no. Other forum posts suggest that the extra characters are connected with the coding that has to be applied to the unit once fitted, to make it work with the car in question. I don't know much about this and would welcome any guidance as to part numbers, coding etc. Thanks