Instruments and Controls Identification Utility Light Switch, Optional Windshield Wiper/Washer Controls Air Wipers Utility lights can be swivel-mounted on top of the cab, mounted on the intake/exhaust support, or flush- mounted in the back of the cab or bunk. They are operated by the utility light switch ( Fig. 2.8 ) which, when turned on, also illuminates a red indicator light on the dash. To operate the air wipers, turn the "Wash-Wipe" knob ( Fig. 2.10 ) clockwise. To increase wiper speed, con- tinue to turn the knob clockwise. Turning the knob counterclockwise decreases wiper speed. To turn the windshield wipers off, turn the knob counterclockwise to its full stop.
When the wiper blades are parked, release the knob. Panel Lamp Control Knob The circuit to the panel lamps is activated by the headlight switch. When the headlights are on, the panel lamp knob ( Fig. 2.8 ) controls the intensity of the instrument panel lamps. Turn the knob counter- clockwise to brighten them and clockwise to dim them. Turning the knob counterclockwise to the peg will also turn off the panel lamps. 1 2 Headlight Switch and Daytime Running Lights A three-position headlight switch ( Fig. 2.8 ) is used to operate the exterior lights. When the switch is up the headlights, and all other vehicle lights, are on. All vehicle lighting is off when the switch is in the middle position.
When down, the switch activates only the clearance, instrument panel, and marker lights, and the taillights. The switch for the headlight high beams is built into the turn signal lever. When the headlights are on high beam, a green light in the warning and indicator light module goes on. The ignition switch must be on for the high beams to operate. 01/18/95 f600433 1. Windshield Wiper/Washer Control Knob 2. Intermittent (delay) Wiper Control Knob Fig. 2.10, Windshield Wiper/Washer Controls The "Delay" switch controls intermittent operation with air wipers. Rotating the knob clockwise in- creases the time interval between wiper strokes.
Turn the knob clockwise until the desired interval is reached. The longest delay is approximately 10 sec- onds between strokes. For vehicles built to operate in Canada, switching on the ignition and releasing the parking brakes auto- matically activates the headlight low beams (later model vehicles) or high beams (earlier model ve- hicles) at half voltage as daytime running lights. The daytime running lights will operate until the parking brakes are applied; then they will switch off. Turning on the regular headlights will override the daytime running lights. The vehicle cannot be driven unless either the headlights or daytime running lights are activated.
The delay knob operates the delay feature only; it will not turn the wipers on. IMPORTANT: After using the intermittent wind- shield wipers, turn off the wiper control ( Fig. 2.9 ) and the intermittent (delay) control. If the wiper control is off, but the intermittent con- trol remains on, that control will continue to cycle whenever the ignition is in the on or ac- cessory position. Continued, constant cycling will shorten the life of the intermittent wiper con- trol. Interrupt Switch Electric Wipers A spring-loaded interrupt switch ( Fig. 2.8 ) temporarily deactivates the marker lights and taillights.
With the vehicle lights on, raise and release the interrupt switch to briefly turn off the marker lights and tail- lights. To operate the electric wipers, turn the knob clock- wise to the first position for low speed. Turn the knob to the second position for high-speed operation. 2.8