Just experienced a weird gremlin on my 00 Land Cruiser.

Symptom:

1 > Unlock door (via key fob or key hole) will trigger the horn to sound (even before the door is open). (no aftermarket alarm or factory stuff as far as I know of)
2 > key fob only unlocks and will not lock any doors
3 > manual key via key hole (driver/passenger/rear hatch) will unlock but will not lock door

It just started to happening yesterday and is driving me nuts cuz every time I have to unlock the door the horn goes off as if it's an alarm. Disabling the horn only works by inputting the (master or slave) key into the ignition and turning it to the "on" position.

I've tried to reprogram the key fob but that hasn't cured this problem. I'm more concerned about the fact that symptom #1 makes me think something is wrong w/ the electrical because I don't understand why the horn would go off when you're unlocking the doors.

Thoughts on how to attack this gremlin?