lets see if i can help
does the alarm arm when you lock the door with the key?
ok well what is mostlikely the problem is the door latch itself. as long as the wires in the door jam arent broken then the rotary switch in the latch is faulty.(This an internal part of the switch and can not be purchased seperately) i have replaced many of these latches for this problem. if you replace the latch you should be all set.hopefully this has answered your question please hit accept so i can be paid for my advice and as always positive feedback is appreciated
ok you will have to remove the exterrior lock you access the screw from the latch side there will be a blk plug ,remove the plug there will be a 25torx screw pull the handle and unscrew the screw till you can you remove the lock. after the lock is removed there is a cable attatched to the handle pop off the cable make sure it goes back on in the same place. then remove the 2 triple square bolts that hold the latch to the door. on the inside of the door there is either 10 mm bolts or 30 torx bolts that hold the inner metal panel to the door.first the window will need to be removed. remove the 2 black plugs about 2" in diameter lower the window till you can see the clamping screws loosen them then lift out the window, then remove all the bolts that hold the inner panel disconnect the wiring harnes then remove the panel the latch will be attatched to the panel replace the latch and reverse the procedure to install. if you are not comfortable with this you may want someone that is more experienced to do this procedure Hope this help