Toyota 2009 Tundra Owner's Manual page 357

Before using the remote controller (for new vehicle owners)
n
When the remote controller battery is fully depleted
n
If the remote controller batteries are discharged
n
The following symptoms may occur.
The rear seat entertainment system control will not function properly.
l
l The operational range is reduced.
When replacing the AA batteries
n
Batteries can be purchased at your Toyota dealer, electric appliance shop, or
camera stores.
Replace only with the same or equivalent type recommended by a Toyota
dealer.
Dispose of used batteries according to local laws.
3-3. Using the rear audio/video system
Remove the cover.
Remove the insulating sheet.
Remove the depleted batteries and install
3 new AA batteries.
3
333