Jeep 2008 Wrangler Owner's Manual page 97

96 UNDERSTANDING THE FEATURES OF YOUR VEHICLE
Also, the rear cargo lamp may be turned on by pressing
the lens. Press the lens again to turn it off.
Cargo Lamp
When a door is open and the interior lights are on,
rotating the dimmer control all the way down to the OFF
detent will cause all the interior lights to turn off. This is
also known as the Party mode because it allows the
doors to stay open for extended periods of time without
discharging the vehicle's battery.
Rear Cargo Lamp (Four-Door Models)