TM 10-3930-659-10 2-22.  OPERATE DEFROSTER FAN (Con’t). c.  Move fan switch (3) to right for slow speed, to left for high speed, and to center to turn off fan (4). 2-23.  OPERATE HEATER AND DEFROSTER. NOTE Heater and defroster obtain heat from engine as It runs.  If engine is not running, heat will not be available for these functions. a.  Start engine (see paragraph 2-11) and bring forklift truck to normal operating temperature. b.  Rotate heater temperature control knob (2) to make temperature setting cooler or warmer, as desired. c.  Rotate heater blower control knob (3) to adjust fan speed from slower to faster,  as desired. TA704515 2-61