TM9-2320-3061-10 2-57. OPERATION OF VAN BODY HEATER (PRIMARY AND SECONDARY) KITS (Contd) (10) Repeat steps 2 through 9 to operate van body secondary heater. Controls for secondary heater are: RUN-OFF-START switch (6), HI-LO switch (7), and red indicator light (8). (11) After all heater operation is complete, place converter selector switch (5) in OFF (middle) position. Close fuel tank shutoff cock (9) by turning clockwise. c. Spot Heating Using Ducts. . (1) Unbuckle straps (3) and (4) as necessary. (2) Remove duct (1) from deflector (2). (3) To operate heater, refer to b. of this para. (4) Direct hot air from duct (1) at equipment to be warmed. NOTE On vehicles with primary heater only, auxiliary duct will be mounted on wall. On vehicles with both heaters, auxiliary duct will be mounted on ceiling. (5) If equipment to be warmed is hard to reach with duct (1), unbuckle three straps (10) and remove auxiliary duct (11). Install auxiliary duct (11) on duct (1). 2-214