RAM 1500 Owner's Manual page 218

216 UNDERSTANDING THE FEATURES OF YOUR VEHICLE
(RKE) transmitter, if equipped. These lights are also
operated individually as reading lights by pushing on the
corresponding lens.
Front Courtesy/Reading Lights
Rear Passenger Courtesy/Reading Light
NOTE: The courtesy/reading lights will remain on until
the switch is pushed a second time, so be sure they have
been turned off before leaving the vehicle. If the interior
lights are left on after the ignition is turned OFF, they will
automatically turn off after 15 minutes.