99 Alarm system malfunction!

I just bought a 99 LHS and it came with a aftermarket auto start. Here's the thing, if you lock the doors and then use the key to unlock the drivers door, the alarm will go off, but if you use the key in the passengers door it will not! it will unlock/lock all doors if you use the key in the passengers door! So I think that the alarm system is not recognizing when the key is in the drivers door, but is when it is in the passengers! The auto start does not work either and I think this door thing is causing the system to not know when to unarm itself! any input would be appreciated!
thanks,
Kalvin

my lhs is the same way,you can disarm the security system on passenger door with key but not drivers door.I think they are made like this