We've just misplaced our second key with remote control. From past experience the alarms comes on when the third key (without remote) is used to open the car. How do I turn off the alarm?

may b the remote might be like a open with a password type ie; with the alarm there will no alarm and without it the alarm produces the sound so remove the old alarm and add a new alarm system that's the solution to this or remov the sound

try unlocking the door with the key- that works on some models.