factory battery disconnect switches were not around back in '07.
only way is that the previous owner installed one. if so, it's usually around the battery/tongue.
or you've got a bad battery or it's getting drained by the parasitic power draws, when not hooked.
without being hooked up to shore power, a battery can be dead in just a few days, without a disconnect switch.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC