Citroen Jumper / Relay (2013) won't lock except for the driver door

[robert_34734]

I literally just got home with my 'new' second hand van, a Citroen Jumper from 2013 (called Relay in the UK it seems).
Only now at home I'm discovering the lock doesn't work! I can only lock the drivers door, which alone doesn't do much of course. I tied the passenger seat-belt around the passenger door in desperation for now

What's happening exactly:

• First of all, the detection of the two rear doors isn't working. The dashboard always warns about the doors being open, even when closed. I just put it down the list of a bunch of small fixes.
• I get the exact same result with the buttons on the key and the buttons inside the cab.
• Pressing 'Lock' causes multiple flashes of the signalling lights, but there is no audible click and the doors are not locked after.
• Pressing cab-unlock or cargo-unlock causes similar flashing of signaling lights with an audible clock of the doors unlocking. The doors are really unlocked after (because they don't lock now...)
• Using the key itself on the drivers door can lock/unlock the drivers door, but all other doors remain unlocked!

My hypothesis is the broken rear door detection makes the central locking system refuse to lock.

Does anybody know what to try for a fix?
Is there a way to manually lock the passenger door? I can't see a button inside nor is there a keyhole on the outside.

I'd appreciate any thoughts, thanks!

[robert_34734]

Found a very similar question about a Jumper / Relay from 2008: viewtopic.php?t=75375
Going through it now to see if it can help me.

[robert_34734]

We took out the plating in the rear doors and we found a bunch of loose connections. I cannot find a connected wire to a sensor or actuator. Which is bad I'm guessing but also confusing, as from the other topic it sounds like disconnecting the wires would bypass the sensors.

On a side note, we got the passenger side to lock manually, using this video from YouTube:


In case it disappears: there is a little hole above the door handle, where you can flip something like a switch. Then after the door from the outside it will be locked. A screenshot from the video:

[robert_34734]

Addition to the above: I found out I can manually lock the rear door, similar to the passenger door:

I removed a little black panel next to the door handle on the inside, exposing a thin metal rod. This rod is connected via a little crank to the lock on the outside, and to what I think might be the electric motor of the central locking system.
Pushing this rod away from the lock slightly causes the lock to engage!

[robert_34734]

Monologue continues. I found:

• The connector to the rear door locking actuator is broken, it doesn't stay in place and I don't know if it still connects electrically.
• Two wires were broken or cut deliberately before the connector and shorted together.
• Undoing this short causes the open-door indicator to disappear and the central locking to work!
• The sliding door sometimes doesn't detect correctly either, it needs a really firm push from the outside. I measured that an open door is seen across the sensing wires as 0 Ohm, while a closed door is measured at around 40 Ohm. (Seems random to me, but okay.) Maybe the same would apply to the rear door.
• When correctly bypassing the rear door detection it still doesn't lock (or unlock actually) through central locking. Either the broken connector doesn't connect at all or the locking actuators are just broken.

I'm not sure yet how to test the locking actuators further.
Also, I posted this on a Dutch camper forum too, here: https://camperforum.nl/viewtopic.php?t=8487521