So I've been having some issues with my central locking actually with door locks and alarm. So my remote locking didn't work on my 98 A4 b5 1.8T ever since I got it and I've been using the key for 3 years. It made a hissing noise from the rear passenger door for some time but since it worked so far I never bothered to fix it. Last month my battery died so I jump started it and I took it for a drive and parked it up after and locked it but to my surprise the key didn't lock the doors. Driver's side door key wasn't locking or unlocking. I could unlock the boot and passenger using key so I locked it and parked it while I sourced a new central locking pump. I found a new pump fitted it and it worked took it for a drive again and got home and I locked the door it all locked. Just to check I unlocked the door and to my surprise the doors didn't unlock fuel cap is locked boot doesn't unlock alarm is not being unarmed. Any ideas why the key doesn't work anymore on any door but the passenger? I thought key unlocked it mechanically without central locking pump involvement and central locking was for alarm and other doors. If I replace the rear door actuator (which is causing the hiss since there seems to be some leak) how can I reset the central locking pump to work again (assuming it's cut itself off to protect the motor). Would battery disconnect work? Is there any way to access boot or fuel cap if the key doesn't work? There is no through access to the boot from passenger seats either.