When i press the unlock or lock button on my car key, nothing happens(i have fitted in a new battery in my key)

You need new batteries in your remote.

IT WORKED!!!! The manual on my 99 ML430 to "Resynching Remote Key" was just written weird.

It says "Turn the key in the ignition to 2nd position then back to 0. Press and hold the lock key for 15 seconds... now press the unlock key 5 times"... which I held down the lock button for 15 seconds, released it, then pressed the unlock key 5 times. NOTHING!

The newer manuals say press and hold the lock key and press the unlock key 5 times (with the lock key still held down).

So... it worked. Hope this helps!

once you fitted new batteries to both fobs you needed to reset the car.....put key in drivers door and unlock/hold key over(windows go down)wait 30 secs then lock/hold over key,(windows go up)wait 30 secs,then press/hold unlock button for 30 secs.you have just reset the system.you have loads of other little gizmos but i will leave you to find them all good hunting....one side parking lights/driveway illumination/and more.
geoff

How
Unlock vehicle. Enter vehicle. Close driver's door. Switch ignition ON and OFF. Remove ignition key. Press and hold unlock button Fig. 2 [2]. Press lock button Fig. 2 [1] briefly 3 times within 10 seconds keeping unlock button [2] depressed. Release unlock button Fig. 2 [2]. Central locking system locks and unlocks rapidly to indicate correct programming. Repeat above procedure if central locking system does not work.
NOTE: A maximum of 4 keys can be programmed. Carry out programming procedure for each key within 30 seconds.

Telephone: Fax: VAT Registration No.:
Infrared remote control
NOTE: Infrared emitter can be seen at front edge of key.
System operation
Switch ignition ON. Ensure clock LED illuminates for 3-5 seconds. Pressing key lock button once activates central locking and alarm. Pressing key lock button twice within 3 seconds activates double locking system.
Programming
When
Key batteries completely discharged. Key batteries not replaced within 15 seconds. Key added or replaced. System malfunction.
How
Obtain all keys fitted with remote control. Turn ignition switch to position I. Wait approximately 10 seconds. Ensure clock LED illuminates.
NOTE: LED illuminates for approximately 5 seconds.
Switch ignition OFF and remove key, while LED illuminated. Programming mode activated for approximately 20 seconds (LED illuminated). Proceed as follows: Point key at receiver (located near interior lamp). Press and hold unlock button Fig. 1 [1]. After approximately 1 second key LED will flash once [3]. Press lock button 3 times Fig. 1 [2]. Release unlock button Fig. 1 [1]. Continue to point key at receiver until LEDs in clock and key have flashed 5 times. Ensure LED remains illuminated. Repeat above procedure within 20 seconds to program remaining keys. To exit programming mode and extinguish clock LED: Switch ignition ON and OFF. Wait approximately 20 seconds.
NOTE: A maximum of 4 keys can be programmed. Fig. 1
Radio frequency remote control
System operation
Switch ignition ON. Ensure clock LED illuminates for 3-5 seconds.


Pressing tailgate release button twice within 3 seconds unlocks the tailgate - if fitted. Pressing key lock button once activates central locking and alarm. Pressing key lock button twice within 3 seconds activates double locking system. Interior lamp illuminates when disarming system.
Programming
When
Key added or replaced. System malfunction.
How
Obtain all keys fitted with remote control. Fasten seat belts and close all doors. From position I, turn ignition switch as follows: To position II. To position I. To position II. To position I. To position II. To position I. Programming mode activated for approximately 20 seconds. LED or fog lamps ON warning lamp illuminates (some models) or the system will emit an acoustic signal to indicate start of programming mode. Proceed as follows: Type 1: Press and hold unlock button Fig. 1 [1]. Type 2: Press unlock button Fig. 2 [2]. Ensure clock LED or fog lamps ON warning lamp flashes (some models) or wait for acoustic signal (indicates correct programming). Wait 2 seconds. Repeat above procedure within 20 seconds to program remaining keys. To exit programming mode: Switch ignition ON. Wait 20 seconds.
NOTE: A maximum of 4 keys can be programmed.

unlock the car with the key then press/hold the button down on the remote to lock car.if this doesnt work try lock the car....etc.

this usually happens when the battery has been disconnected from the vehicle, what happens is when the battery is disconnected the locking system fitted to the car has a pass-code that only the key-fob can access, as a result of the battery being removed the pass-code for the locking system on the car resets and does not recognise the fob being used. Your best chance to get this sorted is to take it into your local garage/dealer and get the fob linked back up to the cars locking system.

Depress lock or unlock button. Manually lock and unlock driver's door within 30 seconds. System should now lock or unlock vehicle. If not, carry out programming procedure.
Programming
When
Key added or replaced. System malfunction: Alarm LED in rear fog lamp switch illuminates for 30 seconds when vehicle is locked.
How
NOTE: A maximum of 4 keys can be programmed (one at a time).
As memory positions of existing keys are unlikely to be known: Obtain and reprogram all keys.
NOTE: Existing key memory positions will be overwritten.
Switch ignition ON. Use key not fitted with remote control. Manually lock vehicle using key. Using first key, press unlock button once (programs memory position 1). Alarm horn sounds once to indicate signal received. Wait 6 seconds. Press unlock button once to confirm programming. Vehicle unlocks. Programming mode deactivated. Switch ignition OFF. To program remaining keys into memory positions 2, 3 and 4. Carry out the complete procedure below for each key: Switch ignition ON. Use key not fitted with remote control. Manually lock vehicle using key. Press unlock button at 1 second intervals, as follows: Twice for memory position 2 (second key). Three times for memory position 3 (third key). Four times for memory position 4 (fourth key). Alarm horn sounds once every time unlock button is pressed, to indicate signal received. Wait 6 seconds. Press unlock button once to confirm programming. Vehicle unlocks. Programming mode deactivated. Switch ignition OFF.
NOTE: Ignition MUST be switched OFF between each key programming procedure

I just go locked out of my X5 BMW 2002 and my key will not unlock the driver's side door! When I press the OPEN button nothing happens... what do I do now?

if you hav a remote control key &yr car wont respond . change key batrrey &contact dealer if still dont work for software