ML500AJL

Hi everyone
I am new to here...
I have a 2004 ML500 W163 with 65,000 km ok her
I am havin problems with the alarm..
I can lock the doors but the lights do not blink @ all
was fine yesterday now the lights do not flash..
and the alarm will go off on it's own with nothing done to the truck
I will unlock and lock the doors from the remote
the light will flash on the dash that the alarm is on
but the lights do not flash showing it is activated
when you unlock the doors the lights flash the one time like before and the doors unlock....
thx u for your help
cheers