S420 driver's door won't lock; trunk door won't close unless I turn key to the left. Any info on possible problem and repair will help. thanks

There is a relay in the rear fuse block for the trunk release. marked trunk relay #36. It is marked on the under side of the lid. If you knew how they worked you could open it by jumping pin 30 to pin 87 in fuse box. on the side of the relay is a diagram of what pins are what . This system uses an electronic control module called ( the BCM ) body control module .When you push the inside release button , that sends a signal to the BCM ,then the BCM activates the relay opening the trunk . Well that won't help ,you won't believe where the fuse box is ! Fuse Block - Rear
In the rear compartment, behind the left wheel well. You could jump the wire at the BCM that goes to the relay. Can't you pull down one of the rear seats to gain access ?

Trunk lock assemble could just need oiled,try that first and if no help it may need to be replaced.....please rate this post and good luck and hope info helps.

Lower the back seat and crawl into the trunk and see what the latch is doing when you activate the key fob. the trunk lid will have to be open to enable any repairs. Also an emergency release cable is probably visible (yellow handle) inside the trunk and will Open the trunk lid.

open the bonnet and place a jumper cable on the starters POS. wire.
Place the NEG. cable from the jumper on any metal structural componant on the vehicle.
use the key fob to 'pop' the trunk.

FIRST: try using the gas release lever from inside the car with the driver side door closed. My 2006 Jetta gas release lever would only work if the driver door were shut and I pulled the release from the inside car interior. Turns out it was a severed door wire (NOT THE RELEASE CABLE). Thus when the door was open, it stretched the damaged wire and so none of the door controls worked unless the door was closed. ie windows, trunk release, and gas release. It was a $600 repair at the dealership, parts and labor! :(

obvious and thats because someone has damaged the lock ,go to dealer and order a new lock for that door with the chassis number and change the lock ,unless the back of the lock mechanism is damaged do the keys turn in the lock and nothing happens or wont they do into teh lock??

The trunk lock is incorporated in the central locking system. This means that you can either lock or unlock the trunk by means of either of the front doors. You can also operate the trunk lock directly with the master key even if the vehicle is centrally locked.

Are you sure it is the Master Key? Try the key in the glove box lock. The power door locks should unlock the trunk for you turn the key if it is right over to the right turn it right over to the left . you turn the key to far right to stop the boot been opened when the doors are not closed.

Keep us updated.

Just a quick note once you hook the battery back up try locking it and unlocking it from the drivers door, if that fails you might try the passenger door. I know on some chrysler products you have to lock and lock again to arm and unlock to disarm. I hope this helps.
Thanks,
Joey

To carry out this procedure you need to have one working key and one key which requires programming. It may help sometimes to hold the key close to the rear view mirror as this is where the sensor is located in most models. 1. With both keys, get in the car and close all windows and doors. 2. Put working key into the ignition and turn to position 1 (the accessories should turn on) (try also position 2) 3. Turn the key back to position 0 and take the key out of the ignition. 4. Using the working key, hold down the unlock button, press the BMW logo (lock button) 3 times, and release the unlock button. Doors should lock and unlock. 5. With the new key, hold down the unlock button and press the BMW logo (lock button) 3 times and let go of the unlock button. Doors should lock and unlock and you're done!! If not working try the following PREPARATION 1. Close all doors, trunk, hood and sunroof. 2. The security system must be in 'disarm' mode. The key must be removed from the ignition key slot. ENTER CODE LEARNING MODE 3. Open trunk and leave it opened. 4. Open the drivers door and sit in the drivers seat. 5. Close the drivers door. 6. Cycle the ignition switch 5 times between the 'OFF' position and position 2,(ignition 'ON', all dash warning lamps will illuminate). The red status LED will illuminate continuously, and the siren will 'chirp' once, to indicate that the code-learning mode has been initiated. ?Do No start the engine.? The Ignition switch cycling in step #6 must be performed within 10 seconds. The sequence in steps #1-#6 must be performed within 45 seconds. REGISTER/DELETE ID CODE(S) 7. Open drivers door, (remain seated in the drivers seat) 8. Close the drivers door. 9. Press and release any button on the remote you wish to register in the system. The status LED will shut off momentarily to indicate that one code has been registered. 10. Repeat steps 7 thru 9 to register the three ID codes. It is possible for the system to memorize a total of 4 different ID codes. As a new code is initialized into the memory, the oldest code is automatically deleted. If you had lost your remotes and wished to delete the lost remote ID codes from the memory, you could initialize the ID codes from a newly purchased replacement transmitter four times thereby deleting the previous ID codes from the system memory. EXITING CODE - LEARNING MODE: 11. Open drivers door, and exit from the vehicle, leaving the door opened. 12. Close trunk. 13. Close drivers door. The LED will turn off and the siren will 'chirp twice. 14. The initialization procedure is now completed; Test all remotes to confirm operation. If this doent work your alarm/central lock needs to be reset