Go to the main control panel for the coach. The big one that is hard wired and has the thermostat controls. On one of the screens there is a place where you can check the status for all the battery powered remotes. That is the first place to look. Now Thor has provided all of us owners with a great resource to help with this kind of thing. On the Thor website under owners resources is a page where you can sign in and provide them with your coach vin number and they will provide you with the manual for every system on your coach. including the Firefly system. There is also an option to print out a list of all the components installed on your coach by model number and serial number. I've had most of the battery powered switches on my coach lose power and a battery replacement has always corrected the issue, sometimes it takes a few minutes for the new batteries to take show up on the master control panel.
Brenda & AL
2017 Thor Venetian, T42 "Groot"
2020 Chevy Sonic, 2019 KTM 790 Duke