Dodge 2004 Ram 2500 Owner's Manual page 136

136 UNDERSTANDING THE FEATURES OF YOUR VEHICLE
NOTE: Dual rear wheel pickup models require properly
spaced rear clearance lights. If such a vehicle is operated
without a tailgate, suitable lights must be installed.
WARNING!
To avoid inhaling carbon monoxide, which is deadly,
the exhaust system on vehicles equipped with "Cap
or Slide-In Campers" should extend beyond the over-
hanging camper compartment and be free of leaks.