stuck double locked rear door

my ultra reliable Prius gen 2 has finally given me a fault after over 2 years of gloriously happy motoring and cheap motoring.
and its an odd fault that has me completely flummoxed.

i have a UK right hand drive Prius gen 2 2006 T4 model.

my rear door on the drivers side wont unlock. it appears to be stuck in double locked mode.
it cant be unlocked manually from inside the car and the lock button just springs back to lock position (as youd expect it to do when in double lock mode)
i can lock/unlock the car other 3 doors using the fob, i can lock/unlock the cars other 3 doors using the internal button on the drivers door.

i suspect there must be a failure of the lock motor or solenoid inside the door but i cant figure out how to get the door unlocked just so i can get the trim off and check.
has anyone ever had this happen to them or can anyone shed any light on what the cause or remedy could be?
thank you

 

i have researched and concluded that the lock will need replacing or i may try to replace the mabuchi motor inside the lock but to get to the lock i need to be able to get past the double lock and open the door.

any suggestions as to how the double lock can be overcome and the door opened?

 

FIXED... for now
i thought that if the mechanism itself is stuck .. maybe if i shocked it it may just release.. so

while the wife was pressing the button on the drivers door to unlock the central locking i was giving the door a hefty slap just near the door handle where the lock would be located.

two slaps later the door unlocked itself.

checked the lock once the door was open and saw that the mechanism was very stiff and the grease on the mechanism had become hard and dry, almost like wax.

cleaned the lock with WD40 and cotton buds till it was moving freely, re-greased it and tested it for ages and seems to have started behaving as it should.

other things others prius owners may find useful from what i did today:

i had stripped the door trim off the other door to have a look at the working of the lock and i had stripped the trim in the hatch.

1) while the door is double locked there is no point in trying to find a manual way of trying to get to double lock to unlock. there is NO WAY that you can pull bits of the lock or pull cables to unlock the door lock. IT IS SEALED and wont allow access to the motor or double lock mechanism. so sticking a hooked wire between the glass and door is pointless.

2) the metal latch on the door frame that the lock hooks onto cannot be accessed from the 'b' pillar. i stripped the hatch side areas to see if i could get to the bolts to cut them if needed but that isnt an option. the nut that the bolts screw into is welded into the door frame and the bolts are short.

3) i also pulled back the rear wheel arch trim to see if i could access the latch that way but that isnt an option either

4) you cant get the doors internal trim off a stuck door unless you are prepared to destroy it. so trying to access the wiring or the lock is virtually impossible if the door is double locked.

5) you can access the wiring of the lock from the rubber tubing on the hinge side of the door. here if you need to try to send current / test the wiring you can do it from there.

Anyway.. i didnt get any help from the forum but never mind i hope this helps anyone else who may have this issue or just make someone aware of the fact that the locks will need regular cleaning and regreasing to avoid this issue arising.