Ignition and Key Switch
The ignition switch is located on the lower portion of the left-hand dash.
The ignition switch has four positions: ACC, OFF, ON, and START. In the OFF position, the key slot is vertical; the key can be inserted and removed only in this position. See Fig..
Fig. 1, Ignition Switche
In the ACC (accessory) position, the key is turned counterclockwise. The auxiliary (bunk) fan, windshield fan(s), radio or stereo system, mirror heat, ether start system, air dryer, backup lights, and all of the electrical systems that are operable in the off position are operable.
The low-beam headlights, taillights, brake lights, road lights, dome lights, clearance lights, turn signals, hazard lights, refrigerator, fuel heater, electric oil pan heater, and electric or diesel-fired engine-coolant preheaters can be operated in the off position (regardless of whether the key is inserted).
In the ON position, the key is turned clockwise. All electrical systems are operable. Low air- and oil-pressure warning lights (or messages) and buzzer operate until the engine is started and pressure is built up. The engine can be started and operated only when the ignition switch is ON.
Note: Switching on the ignition and releasing the parking brakes automatically activates the daytime running lights. The daytime running lights will operate until the parking brakes are applied, then they will switch off. They can also be turned off with an optional override switch.
The ignition key also locks and unlocks the cab doors, the baggage door(s) and if equipped, the bunk door(s).