Suddenly my rear passenger door won’t open either from inside or outside the vehicle. Never had that happen before. Anyone have any ideas / suggestions?

 

Yikes. I admit I don't actually know what the problem is, but at first pass, it sounds like a bad door latch/actuator.

I wonder if since the way the Defender's door cards are mounted with those silver visible bolts, it is possible undo the outer panel from in the car, then undo the inner panel, futz with the latch to manually pop open the door (unlike some cars where you have to destroy the door panel to get at the latch -- which sucks and gets expensive really quickly)

If you're lucky, maybe it will just start working again even if intermittently. That would be very *Land Rover* of it. I'd keep trying it with every lock/unlock cycle. Just to check.

 

Strangely, it started working again. Two things happened. First, it warmed up - so maybe temp played a role. Second, and I think more likely, we’d toggled the child safety locks because our dogs know how to roll down the window. I think some combination of child safety lock and unlock got jammed up on that door - it wouldn’t open inside or from outside - which is weird, but I played with the CL and the regular Lock and it started working again. Just part of the experience :-)

 

There is a TSB for this. its the door rubber that fits against the rear quarter glass jamming.

Mine does it sometimes, but application of some Gummi Pfledge will fix it for several months.

When i does get jammed, its usually when its cold and wet and the Gummi Pfledge has worn off.

See attached TSB

 

While probably not the cause of the above issue, I'll chime in with the TSB. Lubing up the seal is the temp fix, adding the foam strip to the weather stripping is the permanent solution. It is very very simple to do and permanently solves the issue.
I used all of the lubes everyone posted which always made some difference but always wore off, or caused dirt to accumulate on the seal. But the day I just trimmed up a small wedge of foam tape and applied it was the last day I thought about that door issue.
This is one of those driveway fixes you can do in your dress shoes and save yourself a trip to the dealer.

 

Speak for yourself. I do all my driveway fixes in top and tails.

Peasant!

 

A similar problem had just happened to me. The rear driver’s side door (left-hand side here in the USA) suddenly stopped opening — both from the inside and outside. It was working fine one minute, then not at all the next.

I left it overnight, but the issue remained. So I pulled fuse 20 from the passenger-side fuse box, replaced it, toggled the child lock, and then hit the unlock button. That fixed it — door works fine now.