Boot is in locked position but boot open and won't unlock. Key turns in lock but won't unlock boot lock.

Yes you can now exercise your back muscles and patience here remove the hasp on the body work ,easy providing your not as old as me

Went through every site recently but couldn't get the answer.
For my 1985 Toyota corona the answer is.
Firstly open the boot.
1. Look at similar boot in open position.
2. Slide steak knife in at 45 degrees upwards from rear to front under the boot. Ensure the end of the blade is aiming at the lock.
3. Push steak knife handle to left.
Next fix the problem.
A. Search for defective component and replace it.
B. After replacing the basic lock a component still needed to be bent
to activate lock whilst key was turning.
Finally test boot without locking it.
Use screwdriver to click mechanism as if locking, before using key to unlock.

Disconnect and then reconnect your battery will sometimes work...it might be worth a try.

Most likely needs to be re matched to the car.

Two bits of info off the net for you

C CLASS (1993-1997), E CLASS (1995-1997), SLK (1996-)
Procedure
1. Point the remote control at the receiver - this should be located in the driver's door handle or next to the boot lock button.
2. Press the lock/unlock button.
3. Within 30 seconds manually lock or unlock the vehicle using the passenger's door lock or the boot lock.
Alternative method
Procedure
1. Point the remote control at the receiver - this should be located in the driver's door handle or next to the boot lock button.
2. Press the lock/unlock button.
3. Within 30 seconds, switch the ignition ON.
Alternative method
Procedure
1. Point the remote control at the receiver - this should be located in the driver's door handle or next to the boot lock button.
2. Press the lock/unlock button.
3. Within 30 seconds, turn the ignition switch to position II.


and

1. Place key in ignition lock and turn to position 2 [all ignition lights on]
2: Turn key to off position and remove from ignition.
3. Within 10 seconds:
3a: press the Close [Lock] button and hold it down
3b: while the Close button is still depressed simultaneously press the Open [Unlock] button. Press and release the Open button 5 times [still holding the Close button down]
3c: Release both the Close and the Open buttons at the same time, and immediately push any of the two Open buttons once [i.e. either the Open doors or the Open Tailgate]

This information is for the resetting of a previously synchronised key to match the security system after batteries have been removed or replaced. This information does not work with new keys which it seems must be taken to a person with a key synchronisation device [or a super-ripoff-expensive MB dealer]

hope this helps

the wiring around the trunk/boot hinge may be broken/opencircuit. the security system thnks the trunk/boot is open use the manual key to get in to the trunk and repair the wiring

dont know if you recd my previous so again...unlock/hold over windows go down,lock/hold over windows go up/sunroof closes.(alarm/immobiliser resets)....key stuck in lock, pull hard when upright,moving the key up/down when pulling, should do it.also bootlid lock two positions,turn left,then release or turn right and release,see what happens......(boot isolation from the central locking)

the boot lock has two positions full left then upright or full right then upright one of these positions will allow you to remotely open the boot.(it is so that you can lock tho boot and give the service key,which will not open boot/glovebox,to the garage or valet parking.

There are Valet keys (often with a green knob) that will
only unlock the front doors and the ignition but not the
glove box nor boot/trunk.

When either the front door locks or the console button is
pressed, all the doors should lock. Likewise, when either
front door is unlocked, all the doors fuel filler lid and if
selected, the boot will also unlock.

Boot lock has three positions. Unlocked to the left,
automatic with the doors in the center, always locked to the
right. Simply remove the key in what ever position you desire.

The locks can get confused and not work correctly. Simply
sit in the car and manually lock all the doors. That will
usually get the locking module sane again.

All locking and unlocking is done through the switch on the drivers door lock. Put the key in the drivers door and lock and unlock several times. See if the boot opens then.
Or make sure you haven't hit the lockout button on the drivers door that stops anyone else from opening their doors. (Including the boot.)

try locking the car then disconnect the boot lock. then unlock the car and reconnect the boot lock,it sounds as though its out of sinc with the rest