In my MH it's under one of the seats. To access it I have to remove the drawer in the seat.
I found mine by putting the system in test mode then listening for the beeps from each speaker. Mine also has an on/off setting on the remote so had to do it twice since the remote doesn't indicate whether you've turned it on or off with the press of the button.
US Navy Vet, Liberty Tree Member of Oath Keepers, NRA & VFW Life Member, Alaska EMT.
2009 Safari Cheetah 40 SKQ
2009 Winnebago Chalet 231CR