(3) Make certain emergency switch (6)
is in the ON (up) position.
(4) Start engine (refer to paragraphs
2-12 and 2-13).
(5) Depress press-to-test indicator lamp
(4) on control box to check operation of
circuit. Be sure test lamp (4) lights.
(6) Set HI-LO switch (3) on control box in HI or LO
position, depending upon heating needs.
(7) Turn run-off-start switch (5) in control box down to
START position. Hold in that position until indicator lamp
(4) again lights. (Switch is spring-loaded and must be held
down for at least 9 seconds.)
If switch (5) is moved to RUN position before indicator lamp (4)
lights, heater will not operate.
(8) As soon as indicator lamp (4) lights, turn switch (5) to RUN position, with no
hesitation at OFF position.
If heater fails to start, turn switch (5) off and repeat operations (3)
through (6) above. If heater fails to start after two attempts, notify
organizational maintenance that service is required.
(9) Adjust hot air flow with heater air control handle (2). Adjust defroster control
handle (1), as required, for defrosting. All heated air is directed at the windshield when
defroster control handle (1) is pulled all the way out. Preheat cab before defrosting
windshield to avoid glass damage from sudden temperature changes.