Alarm Malfunction

After reading some thread covering similar problems, it appears my best bet is to disable the factory alarm system on my '87, 560SL. Here's what happens, I can only lock and unlock doors and trunk at the trunk lock without the alarm sounding when I unlock the doors. The driver's door does not lock all locks, the passenger door does, but if I use the door locks, the alarm goes off when I unlock at the doors. What do you think? Also, where do I find the disconnect on the factory alarm system.