Ignition Switch and Key

The ignition switch (Fig.) has four positions: ACCESSORY, OFF, ON, and START. In addition, the same key locks and unlocks the cab doors.

Fig. 4.1, Ignition Switch Positions

Fig. 1, Ignition Switch Positions

In the OFF position, the key slot is vertical; the key can be inserted and removed only in this position. The following can be operated in the off position (regardless of whether the key is inserted): The low-beam headlights, taillights, brake lights, road lights, dome lights, clearance lights, turn signals, hazard warning lights, horn, CB radio, power windows, cigarette lighter, clock, and electric oil pan heater.

In the ACCESSORY position, the key is turned counterclockwise. The radio, stereo system, mirror heat, air dryer, backup lights, and all of the electrical systems that are operable in the off position are operable in the accessory position.

In the ON position, the key is turned clockwise and all electrical systems are operable. The low air pressure and low oil pressure warning lights (or messages) and buzzer operate until the engine is started and pressure is built up.