#1 cause of this is low trailer battery, not actual propane or CO issues.
do you have the trailer plugged in all the time, to keep the battery charged up?
if you don't, the detector and other parasitic power drains will empty a single batter in just days. and if you don't get on it soon, the battery will be permanently damaged by depleting it too low.
rarely, it's a bad propane/CO detector unit.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC