58
Check Air System for Leak Down — Disconnect the
gladhands from the trailer. Run the engine at fast idle and
allow air pressure to stabilize at 120 P.S.I. for at least 1 minute.
Shut off the engine and observe the dash gauge(s) for 2
minutes. The drop in pressure should not exceed 2 P.S.I.
(0.137 bar) over the 2-minute period.
Check Operation of Back-Up Alarm — With the engine
running, move the gear selector to reverse and listen for the
back-up alarm.
Check HVAC System
Blower Motor Operation — With the key on, ensure that
the blower motor operates at each position of the blower
speed switch.
Temperature Control — Confirm proper operation of the
temperature control switch.
Defroster Operation — With the engine running and the
defroster control turned on, confirm air flow from the
defroster vents.
Air Conditioner Operation (if applicable) — With the
engine running and the air conditioner control turned on,
confirm cooled air flow from the defroster vents.
Auxiliary Fan(s) (if applicable) — With the key on, turn on
the auxiliary fans and confirm operation.
Check Fifth Wheel Unlatch Control — With the system air
pressure above 100 P.S.I., confirm that the fifth wheel jaws
unlatch when the dash control is activated.
Check Operation of Boom — With the engine running at fast
idle, activate the boom control and ensure full extension and
retraction.
Check Operation of Windows — Confirm that all regulated
and sliding windows open and close fully.
Check Door Latch Operation — Operate the door latch from
inside and outside the cab to ensure proper operation.
Check Dome Light Operation — With the key on, turn on the
cab dome light and confirm operation.
Check All Glass and Mirrors — Inspect all glass and mirrors
for cracks and breaks.
Check Fire Extinguisher Charge (if applicable) — If the
vehicle is equipped with a fire extinguisher, confirm that it is
properly charged.
6 Scheduled Maintenance