I've had this problem for a few years and I'm finally fed enough to register here and see if I can get some help.

Vehicle: '98 Ranger XLT w/out key fob.
Issue: Unlocking door doesn't deactivate alarm.
Recreate: Lock the doors (either externally with key or internally with button). Unlock either door from the outside with key. Lift door handle. HONK HONK HONK. Jump in truck, turn key in ignition to shut off the alarm. This doesn't happen every time, but say 66% of the time. 33% of the time it works as expected and there is no alarm.
Remediation: None. I've tried locking and unlocking from the outside multiple times before open the door, but it doesn't effect the situation. Obviously leaving the door unlocked keeps the alarm from triggering.

Has anyone seen this? Anyone got advice? What should be happening when the key is turned to shut off the alarm (that isn't happening)?

Thanks

 

Factory or aftermarket alarm? Either way, the key will not change alarm state, only the keyfob can do that. The alarm has no way of knowing that an authorized key was inserted into the door lock.

 

Factory system.

Correct me if I'm wrong, but if working correctly, the alarm (honking) should trigger when a locked door is unlocked by some means other than the key, correct? Most folks only experience this when the door is unlocked by reaching through an open window and pulling up the mechanical door lock. It should not not go off when the key is used to unlock the door. In my case it does.