RAM 1500 Owner's Manual page 696

694 STARTING AND OPERATING
Improper Adjustment Of Weight-Distributing Hitch
(Incorrect)
Recommended Distribution Hitch Adjustment
Towing With 1500 Air Suspension
1. Set air suspension to normal ride height. No action is
required if already in normal ride height.
NOTE: The vehicle must remain in the engine running
position while attaching a trailer for proper leveling of
the air suspension system.
2. Position the truck to be ready to connect to the trailer
(do not connect the trailer).
3. Under radio suspension settings, turn on jack mode.
Jack mode will be canceled and procedure must be
restarted if the vehicle is driven at speeds above 5mph
(8kph).
4. Measure the height of the top of the front wheel
opening on the fender to ground, this is height H1.