2002 MB ML320 car alarm problem the alarm sound coming out... after I locked the car door. supposed the car alarm turned on without any sound after locked the car door. Now, the alarm sound come out after I locked the car door. please teach me how to reset the car alarm system.......thanks. Patrick

To arm content theft alarm.
1. Open the door.
2. Lock the door with the power door lock switch or
the remote keyless entry transmitter. The
SECURITY light should flash.
3. Close all doors. The SECURITY light should go off
after approximately 30 seconds. The alarm is not
armed until the SECURITY light goes off.

If a locked door is opened without the key or the remote keyless entry transmitter, the alarm will go off. The headlamps and parking lamps will flash for two minutes, and the horn will sound for 30 seconds, then will turn off to save the battery power.

Mercury Mountaineer 2002 2005 Factory Service SHop repair manual Download

for the easy solution download the pdf file

try this first, make sure all doors are locked. Insert door key in drivers side door lock and turn key left for 3-5 seconds then turn to the right with a little pressure. open door. Insert key in ignition and turn to on ONLY! wait at least 30 seconds, then turn key to start allow to idle for a few minutes. If problem persists, the remote is not functioning properly. contact a locksmith for reprogramming or replacement. A lock shop will be cheaper than the dealer! Hope this helps you!

If you just do not want the alarm sounding when locking unlocking the car find the alarm (horn ) and disconnect the wires to it

this is a factory alarm, the problem is the alarm is active, you will need to use the door locks to turn alarm off, insert key in driversdoor and lock and then unlock door this will turn alarm off, if that doesnt work then use pass/side door, the lock has a built in switch that knows when the door is locked or opened, the driversdoor may have a bad switch so inturn the computer thinks the door was forced opened without key and it is turning alarm on, so again use the key to unlock door try the pass/side if driversdoor doesnt work. good day

Lot's of things can make it do it but with the drivers door window open. close and lock all the doors. ( said close the doors as in open them and close them back and make sure they close good ) Once all locked up unlock the drivers door with the key twiced once unlocks the door the second time it unlocks all the doors and the thrid time it'll unlock the hatch too. If it does'nt and the alarm is still going off open the hood and close and lock all the doors again. disconnect the battery, ( the alarm will certainly stop then), With the battery disconnected and all the doors closed and locked, put the key in the ingtion and turn it to run ( nothing will happen as the battery is disconnected ) This next part is important. The batterycables should be clean anyway but if their not they need to be clean for the next operation. With them clean put the positive on first and tighten it down now put the negiative onlike you mean it ( don't let it bounce and connect it. The alarm should'nt be going off as the car has the key on. Reach in and start the car ( I did'nt say open the door). with it running it should'nt be alarming either. Turn the key off and remove it them open the door and get in and restart the car itshould be back to normal.. Most of the time one of the door switches said to the computer that it was opened as it was supposed to be locked or it was opened after it was supposed to be locked and you left.

its probably the key alarm the lock cylinder may need to be replaced

their is a metal bar that connects to the door lock ,and the drive for this bar on the back of the lock has broke ,regular thing this the bar is only about 3 euros and comes in a bag with all the other little bits as well,look on end of door and behind the a rubber grommet in line with the door handle ,take this screw out ,open door handle and pull towards end of door and the handle comes off .then you will see what i mean

probably a leak in the air line to that door, therefore not reaching pressure.
The central locking should work on compressed air
would need to strip door panel down and check lines and listen for air leaks when operated

The Alarm on my Mercedes ML320 sounded every night, then it started doing it more often, Showed it to the dealer he says it's the 'Tow Sensor', that needs to be repaced. $700, down the drain. I have already started hating this car, it eats $500-600, every 6 months...