My side door would also never open once I had deadlocked it. The knob inside would lock but would never unlock until it finally did catch with repeated unlocking with fob so I taped up the 3 contacts with insulating tape and just left side door unlocked. Obviously this very risky but apart from when working it lives in a drive off the beat and track so wasn't a biggie. However the beeping was getting annoying and after a roadside pull and needing the horn for their random check it was best get this sorted.
Anyway back to the fixing I was removing the knob tonight and sccidentky locked it and with the contacts taped
and there no way to play about with central locking until it unlocked. I'm sure other locks have same trouble and no messing will unlock so this will be useful to those who can't get side door open. Having got another lock out scrappies I watched how the deadlock worked and there a lever you can access if you get the panels off and at the bit adjacent to the knob that you can see you twist back the metal with a screwdriver then using a flathead if you go in at a 45 degree angle you should feel the lever and you push down to lift it up and then open with handle n voila door opens.
Once open you can remove lock and replace with a working one. Van now secure again and unlocks and no more beeping of horn at 3am.
Ive attached pics to show where I did it. Hope all this helps someone
On a side note I also had a flashing door open on the dash but that was caused by a loose earth on the wheel arch along from the fuse box. Seems to work itself loose over time but add a couple of washers and it's tight again.
