Fuel Flap Actuator problem

HI, I've a '99 Passat TDI and recently when I went to fill up the fuel tank I found the Flap Covering the Fuel filler Cap was stuck on lock even though I has pressed the flap release button (beside handbrake). Ended up driving home on reserve and found out where the fuel flap actuator was located and manually removed it to release flap so I could fill up. I suspected a blown fuse but on inspection all fuses are ok, so next I suspected the Actuator, which is like a motorised plunger which attaches to an arm which locks the flap . Got a brand new one from dealer (he described as central locking boot actuator), but made no difference since replacing.
Has anyone else had this problem or can suggest something else to check to try and fix. Any help or advice much appreciated.

Thanks

Could try the switch. Could only be that or the wiring. Nothing else left to check if the fuses are ok and the solenoid is brand spankers!

Hi, just replaced the console switch (again from dealer) and no difference. Would be surprised if was wiring as connectors seem in perfect condition though I suppose wont know till tested, only I havent got a tester. One thing I have noticed is that passenger door also fail to lock with central locking. Is there a central locking relay or anything else in the circuit which may link these to problems?.

Your 1999 Passat should have a semi-pneumatic central locking system, virtually identical to its sister vehicles, the Audi A4/A6.

The fuel flap release is most probably routed through the central locking pump first.

A common problem with this type of pump is the location, they can tend to become water-logged, causing unexpected window opening/closing, and electronically controlled boot/fuel flap problems.

How long does your locking pump run for when you lock/unlock the car?

sorry if stupid question but how can you tell how long pump runs for? Is the pump located in the passenger foolwell under carpet - I've been reading various related threads and the more I read the worse it seems to be. Theres serveral references to the CCM (comfort control module) which is apparently located in the footwell and can be the cause of many eletrical problems such as E/Windows, C/Locking ant interior lights. My car has also had problems with interior light not coming on which seems to fit the bill. They only problem is those have been caused by water ingress due to blocked drian plugs in engine bay causing water to enter the footwell, identified by wet carpet. I've just checked my carpet and it's bone dry, though still think it's worth lifting the carpet to check CCM wiring. Is the pump you mentioned located there aswell? Thanks

The earlier cars had pneumatic central locking (generally upto 2000ish)

The pump is located in the boot, you can hear the pump working for a second or so when locking/unlocking on standard cars.

Later cars have an entirely electronic locking system.

I would defo try lifting the passenger carpet. especially if you have had other electrical faults recently.