Sorry for bring the tone down of this forum but as I always found that as people here are very helpfull I thought I'd chance my arm.

My wife's car (VW Jetta MK5 model) has a central looking problem.
We already replace the Front passenger door a few weeks ago as it would not lock anymore.
Now the whole drivers side is giving problems - driver -, passenger and fuel cap. The doors won't unlock and the fuel cap won't lock.
The doors can be unlocked from the inside so the mechanism works manually. The Airbag warning light has come on recently as well - but this may be just coincidental?

We'll probably bring it in to the garage but I am hoping to get some idea as to the cause of the problem.

Again apologies

try checking your fuses first

Check the earth from the battery to the car, Negitive terminal
bad earths are a coman cause of problems

Just checked the fuses and they're OK. Will check the battery tomorrow...
I did noticed that there is a slight buzzing sound which seems to come from the passenger door.

According to my wife the problem seems to be intermittend as it comes and goes...

look very closely at gauges if they flick or bounce when this trouble arises its most likely as mentioned a bad ground body to frame or battery cable or from main fuse block to body comonly behind drivers toe kick pannel upper area on several makes of cars and trucks good luck pal

Could be a blow fuse, is the interia light working? Fuses are on the left or right side of the dash depending on left or right hand drive vehicles.

First try a terminal 30 reset, key out of the ignition, disconnect the neg side of the battery for 2 min then reconnect. Sometimes the can bus diagnostic interface in the VW's get corrupt & the only way to reset it is to power down the interface.

When you replaced the door did you use the old window motor/ECU. If you did not use the the old ECU you need to recode the new doors ECU using the old ECU's coding, otherwise you will have the convenience ECU talking to both front door ECUs in different codes.. Normaly you only need to replace the door lock because of the F122 micro switch not telling the door ECU that the door is closed or open, never seen a whole door replace for this problem.

I have seen a few Golf & Jetta 5's brake the wiring between the door & A pillar in the rubber boot, check the wiring in the rubber boot. If you want to check the eath points for both front door ECU's they are on the inside of the A pillars just under the carpet.

Cheers for the replies so far lads. Won't get the chance to check it before the weekend as we're heading of for a 2 day wedding ...
I'll hopefully get a chance to do some checks on Sunday.