Driver Controls and Instruments Instrument and Control Panel lease the key. When released, the key will move to the ON position. Figure 3.1 represents a typical dash equipped with all of the standard and many of the optional instruments and controls. In the ON position, all electrical systems are operable. Warning lights and buzzer for low air pressure and low oil pressure operate until the engine is started and mini- mum pressures are built up. Warning and indicator light modules, located on each side of the speedometer, house all of the standard and optional warning and indicator lights. Figure 3.2 identi- fies the warning and indicator lights. Panel Light Control The panel lights (see Fig.
3.4 ) are turned on by the headlight switch. The panel light control lever adjusts the brightness of the instrument panel lights. Slide the control lever up to brighten the lights, and down to dim them. Move the control lever all the way down to turn them off. Controls Ignition Switch and Key The ignition switch can be turned to four positions: OFF, ACCESSORY, ON, and START. See Fig. 3.3 . The igni- tion switch key also locks and unlocks the cab doors. Headlight Switch and Daytime Running Lights The key can be inserted and removed only from the OFF position.
The headlights (low beam only), brake lights, fog lights, dome lights, clearance lights, turn sig- nals, hazard warning lights, parking lights, and the cigar lighter operate with the ignition switch off, regardless of whether the key is inserted. In the up position all of the lights are off. See Fig. 3.5 . Turning the switch clockwise one position turns on the marker/clearance lights, taillights, parking lights, license plate light, and panel lights. Turning the switch clock- wise another position turns on the headlights, marker/ clearance lights, taillights, parking lights, license plate light, and panel lights.
In the ACCESSORY position, the wipers, heated mir- rors, backup lamps, radio, ether start system, and all electric gauges operate. Turn the key fully clockwise to the START position, only when starting the engine. When the engine starts, re- 3.1