TM 10-3930-659-10 2-2.  CONTROLS AND INDICATORS (Con’t). KEY CONTROL OR INDICATOR FUNCTION 27 Adjustable Floodlight Switch Operates adjustable floodlight. 28 Starting Aid Switch Operates engine cold start aid. 29 Ignition Switch Operates cab accessories, Instrument panel BULB CHECK, ignition switch ON position, and engine start. HEATER CONTROL PANEL KEY CONTROL OR INDICATOR FUNCTION 30 Heater Blower Control Operates heater blower motor. 31 Defroster Blower Control Operates defroster blower motor. 32 Temperature Control Operates heater/defroster temperature range. TA704475 2-5