Just to let you guys know that any sensor that you have on the system will reinstall itself if you do the following and it will keep its original security code. take out the batteries on the sensor for about four hours or until you see the light for that zone start blinking then but your batteries back in the sensor, press the test button, then put your system in the install mode and then activate the sensor and it will then reset back to the code and position it was at originally. Also with the big red button have you tried it with it close to your unit or always mounted some where. maybe you are getting interference with something or maybe you need to try to do something to increase the signal strength.