Driver Controls

Steering Column and Left-Hand Dash Controls

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. 5.1 .
Fig. 5.1, Ignition Switch
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).

Headlight Switch

A three-position headlight switch on the left-hand dash is used to operate the exterior lights. When the switch is in the upper-most position, the headlights and all other vehicle lights are on. All vehicle lighting is off when the switch is in the middle position. When the switch is in the downward position, only the clearance, instrument panel, marker lights, and the taillights are illuminated. See Fig. 5.2 .
  • 1. Turn Signal/Hi-Low Beam Switch
  • 2. Hazard Light Switch
  • 3. Headlight Switch
  • 4. Utility Light Switch
  • 5. Ignition Switch and Key
  • 6. Tilt/Telescope Pedal
Fig. 5.2, Steering Column and Left-Hand Dash
Switching ON the ignition and releasing the parking brakes automatically activates the daytime running lights, if equipped. The daytime running lights will operate until the parking brake is applied or the headlights are turned on.

Utility Light Switch

Utility lights can be swivel-mounted on top of the cab, mounted on the cab side-extender, or flush-mounted in the back of the cab or sleeper. They are turned ON and OFF using the switch (UTLY LAMP) located next to the headlight switch. See Fig. 5.2 .

Turn Signal Lever

The turn signal lever is mounted on the steering column. See Fig. 5.2 . Moving the lever counterclockwise turns on the left-turn signal lights; moving it clockwise turns on the right-turn signal lights. When one of the turn signal lights is on, a green indicator light flashes at the far left or far right of the warning and indicator light panel. To cancel the signal, move the lever to the neutral position. Some style levers may have automatic cancelling, and the turn signal lever automatically returns to the neutral position when the steering wheel returns to the straight-ahead position after a turn.

Headlight Dimmer

Pull the turn signal lever toward the steering wheel to change from low-beam to high-beam headlights or from high beam back to low beam.
When the headlights are on high beam, a blue light on the indicator light panel comes on. For vehicles built to operate in the United States, switching from low beams to high beams will switch off the road lights.
NOTE: The ignition switch must be on for the high beams to work.

Hazard Warning Light Switch Tab

The hazard warning light switch tab is located underneath the turn signal lever. See Fig. 5.2 . Hazard warning lights are operated by pulling the tab out. When the hazard warning light switch tab is pulled out, all of the turn signal lights and both of the indicator lights on the control panel will flash. To cancel the warning lights, move the turn signal lever up or down.

Adjustable Steering Column

Make sure that the steering column is locked before driving the vehicle. Never tilt the column while driving the vehicle. Doing so could cause loss of vehicle control, personal injury, and property damage.
For the optional tilt-steering column, the control pedal is located on the column below the steering wheel. See Fig. 5.2 .
After adjusting the seat to the desired ride position, unlock the steering column by pushing and holding the control pedal all the way down. Tilt the steering column to the desired position, then release the control pedal to lock the steering column in place.

Electric Horn

The button for the electric horn is located in the center of the steering wheel. To sound the horn, press down on the button. The horn will sound for the duration that the button is pressed, up to 60 seconds. The electric horn will operate regardless of the position of the ignition key.

Door Mounted Controls

The driver's door control panel has power switches to control the driver's and passenger's windows, door locks, and door mirror adjustments. See Fig. 5.3 .
  • 1. Passenger-Side Window Switch
  • 2. Driver-Side Window Switch
  • 3. Door Lock/Unlock Switch
  • 4. Mirror Selector Switch
  • 5. Mirror Directional Switch
Fig. 5.3, Driver's Door Mounted Switches
Power windows are standard on 122SD and Coronado vehicles. In addition to the control on the driver's door, the passenger door has a switch mounted in the top of the door, that controls the passenger-side power window.
IMPORTANT: There is no anti-pinch protection when the window is almost closed. Be sure to clear all objects from the window before closing.
The window switches have three positions: lower window, neutral, and raise window. Press forward on the switch to raise the window. Press the switch in the rearward position to lower the window. Hold the switch down for approximately one second to activate the express function; the window will continue to roll up or down after the switch is released.
Pressing the power door lock switch opens or locks both the driver's and passenger's doors simutaneously.
To adjust the mirrors, first use the selector to activate either the left or the right mirror, then use the directional switch to aim them inward, outward, upward or downward. See Fig. 5.3 .

Air Horn

Air horns may be mounted on the roof of day cabs, or under the driver-side floor for sleeper cabs. The air horn is controlled by a wire lanyard that hangs down inboard by the driver’s door. See Fig. 5.4 . Pull downward on the lanyard to sound the air horn.
  • 1. Lanyard
Fig. 5.4, Air Horn Control

Lower Right-Hand Dash Panel Switches

The lower right-hand dash has a small electrical switch panel with room for three switches. Typically it houses the panel lamp dimmer switch, the footwell courtesy lamp switch, and the mirror heat switch. See Fig. 5.5 .
  • 1. Panel Lamp Switch
  • 2. Foot Well Courtesy Lamp Switch
  • 3. Mirror Heat Switch
Fig. 5.5, Lower RH Dash Panel Switches

Panel Lamps Control Switch

The circuit to the panel lamps is activated by the headlight switch. When the headlights are turned on the panel lamps are illuminated. The intensity of the instrument panel lamps can be controlled with the panel lamp switch. Slide the switch toggle up to brighten them and down to dim them. See Fig. 5.5 .

Foot Well Courtesy Lamp Switch

Courtesy lights illuminate the footwell area on both sides of the cab, and the bottom of the door panels. The driver's courtesy light is located on the steering column and the passenger's footwell light is located on the lower right dash panel. There is also a courtesy light in the lower portion of each cab door. The courtesy lights activate when a door is opened or with the dash switch. See Fig. 5.5 .

Mirror Heat Switch

The outside mirrors can be heated to keep them clear of fog, frost, and ice. In order for the heated mirrors to operate, the key must be turned to ON. Press the upper part of the mirror heat switch to activate it. See Fig. 5.5 .

Main Dash Switches

See Fig. 5.6 for a general layout of main dash electrical switches.
NOTE: See Chapter 10 in this manual for details on operating the cruise control, and the engine brake.
  • 1. Windshield Wiper/Washer Switch
  • 2. Cruise Control Activate Switch
  • 3. Cruise Control Settings Switch
  • 4. Engine Brake ON/OFF Switch
  • 5. Engine Brake Level Switch
  • 6. Optional Switch
  • 7. Optional Switch
  • 8. Engine Fan Switch
  • 9. Marker Interrupt Switch
  • 10. Regen Switch
  • 11 ATC Switch
  • 12. Dome Lamp Switch
  • 13. Bunk HVAC Override Switch
  • 14. Shutdown Override Switch
Fig. 5.6, Main Dash Switches

Marker Lights Interrupt Switch

The marker lights interrupt (MRKR INT) switch temporarily deactivates the marker lights and taillights. With the vehicle lights on, raise and hold the paddle switch to briefly turn off the marker lights and taillights. To alert the driver that the switch is functioning, the dash lights will flash with the marker lights when the switch is actuated. When the paddle is released the marker lights will return to normal operation. See Fig. 5.6 .

Road Lamp Switch

The optional road lamp (ROAD LAMP) switch (see Fig. 5.7 ) operates the road lights mounted on the bottom edge of the front bumper or recessed in the front bumper.
For vehicles built to operate in the United States, the low beam headlights must be turned on before the road lamps can be turned on. The road lamps will not illuminate if the high beam headlights are already on, and switching from low beams to high beams will switch off the road lamps. For vehicles built to operate in Canada, the marker lights must be on before the road lamps can be turned on.
Fig. 5.7, Road Lamp Switch

Regen Switch

A parked regen of the aftertreatment system can be initiated with the regen switch. See Fig. 5.6.
Refer to Chapter 11 for instructions on how to perform a parked regen.
An optional inhibit regen switch provides additional control over the aftertreatment regeneration process. When activated, the inhibit switch will stop a regeneration cycle in progress, and prevent the start of a regeneration cycle until the switch is no longer active. See Fig. 5.8 .
Fig. 5.8, Regen Inhibit Switch

ATC Switch

The Automatic Traction Control (ATC) switch is a momentary switch. Briefly push the top of the switch to activate or deactivate it. See Fig. 5.6 .
The ATC system limits wheel spin when power is applied to the drive axles during reduced-traction situations. When the ATC is active, the ATC will apply gentle braking to the spinning wheel, to force power to the wheel(s) with better traction. If both wheels are spinning, the system will signal the electronic engine to reduce power.
Pressing the ATC switch will temporarily allow more drive wheel spin, to help burn through a thin layer of ice, or to help throw off accumulated mud or snow. When the switch is activated, an ATC or WHEEL SPIN icon located in the driver's message center will blink slowly. Pressing the switch again will cycle the system back to normal operation.

Engine Fan Switch

The engine cooling fan can be manually activated with the engine fan switch. The fan will continue to operate for a set amount of time and then turn off unless the coolant temperature is high enough to continue the fan operation. To turn the engine fan on, press on the upper part of the switch. Press the bottom of the switch to deactivate it. See Fig. 5.6 .

Trailer Auxiliary Switch

Trailers that are equipped with pneumatic brakes and used in North America or South America are generally equipped with an electrical cable that terminates in a 7-way connector. Power for the trailer lights is passed from the vehicle to the trailer via the primary receptacle, controlled by the dash switch. Press the top of the Trailer Auxiliary switch to activate it. Press the bottom of the switch to turn it off.

Windshield Wiper/Washer

Dash Controls

The wipers are operated by a double-paddle WIPER/WASH switch mounted on the main dash panel. The top paddle, when pushed in, turns the wipers on (if they are off) or off (if they are on). When it is pushed up, the top paddle switches the wipers to high speed; when it is pushed down, it switches them to low speed. See Fig. 5.9 .
  • A. Push in to turn wipers on (low speed) or off.
  • B. Push up for high speed.
  • C. Push down for low speed.
  • D. Push in momentarily for mist cycle. Push in and hold in for wash cycle.
  • E. Push up for fast delay. If already in delay, push up for the next faster delay.
  • F. Push down for slow delay. If already in delay, push down for the next slower delay.
  • 1. Locking Clip
  • 2. Wiper/Washer Switch
  • 3. Light Bulb Screw
Fig. 5.9, Wiper/Washer Switch Operation
The bottom paddle, when pushed in, turns the washers on. When pressed for less than 1/2-second, the wipers will perform a single, low speed dry wipe (mist function). When pressed for more than 1/2-second, the wash cycle begins and continues for three cycles or until the paddle is released. When the bottom paddle is pushed up, the wipers operate in fast delay. When the bottom paddle is pushed down, the wipers operate in slow delay. With the wipers in delay mode (fast or slow), push the bottom paddle up to shorten the delay period or push the paddle down to lengthen it.
Do not move the wiper arms manually. Wiper motor damage will occur if the arms are moved.

Windshield Washer Fluid Reservoir

The windshield washer reservoir is located under the hood, near the firewall on the driver's side. Remove the cap from the filler neck to add windshield washer fluid.

Guarded Switches

IMPORTANT: The following switches are guarded to prevent unintentional switch activation. See Fig. 5.10 .
  • 1. Suspension Dump Control
  • 2. Interaxle Differrential Lock
  • 3. Fifth Wheel Slide Lock
  • 4. Traction Control, Rear Differential
  • 5. Traction Control Forward Differential
Fig. 5.10, Guarded Switches

Air Suspension Dump Control

The air-suspension height switch may be used to aid in connecting or disconnecting from a trailer. When the switch is set to LOWER, the air-suspension dump valve deflates the air springs to lower the rear of the vehicle. When the switch is moved back to the normal position, the suspension will return to the correct ride height. A guard is positioned around the switch to minimize accidental activation. See Fig. 5.10 .
Do not operate the vehicle over uneven ground such as ramps, speed bumps, curbs, etc. with the air springs deflated. Doing this may lead to air bag separation from the piston, preventing the suspension air springs from reinflating.
Never exhaust air from the suspension while driving. When the air is exhausted, the suspension will not absorb road shocks, and components may be damaged.

Interaxle Differential Lockout Control

The interaxle lock should only be engaged when the vehicle is moving slowly at low throttle. Engagement at high speed or power can damage the axle(s).
The interaxle lock, standard on all dual-drive vehicles, is driver-actuated by means of a LOCK/UNLOCK control valve switch mounted on the control panel. See Fig. 5.10 . A red indicator light comes on whenever the interaxle differential is locked out (switch is in the lock position; no differential action between the drive axles). A guard around the switch minimizes accidental activation.

Fifth Wheel Air Slide Control

Do not activate the fifth wheel slide control valve while the vehicle is in motion. To do so could cause damage to the fifth wheel member, the kingpin, the cab or trailer, and ultimately to the drivetrain.
The fifth wheel air slide valve permits repositioning of the sliding fifth wheel from inside the cab. Moving the air slide control valve switch to the lock position deactivates the control valve and locks the fifth wheel to the baseplate. See Fig. 5.10 . Moving the switch to the unlock position activates the control valve and unlocks the fifth wheel slide mechanism, allowing changes to the total length of the tractor-trailer and changes to axle loads to comply with varying state or provincial laws. A red indicator light, if so equipped, is illuminated whenever the fifth wheel slide is unlocked. A guard is positioned around the switch to minimize accidental activation.

Controlled Traction Differential Control

A controlled traction differential feature is included or available as an option on some rear axles. A control valve switch engages and disengages the controlled traction feature to cause the axle shafts to rotate together. See Fig. 5.10 . The controlled traction, or differential lock, should only be engaged when the vehicle is moving slowly at low throttle to avoid causing internal axle damage. The differential lock must only be used for adverse road conditions. The use of the lock increases the turning radius and affects the vehicle handling. A guard is positioned around the switch to minimize accidental activation.

Dash-Mounted Brake Controls

Parking Brake Control Valve and Trailer Air Supply Valve

Do not step on the service brake pedal while the parking brakes are applied. To do so can cause damage to the brake mechanisms.
The yellow diamond-shaped knob operates the parking brake valve. Pulling the knob applies both the tractor and the trailer spring parking brakes. See Fig. 5.11 . Pushing the knob in releases the tractor spring parking brakes. Before the spring parking brakes can be released, the air pressure in either air brake system must be at least 65 psi (447 kPa).
  • 1. Trailer Air Supply Valve Control
  • 2. Parking Brake Control Valve Control
Fig. 5.11, Dash Brake Valve Controls
The red octagonal-shaped knob operates the trailer air supply valve. See Fig. 5.11 . After the vehicle and its air hoses are connected to a trailer and the pressure in the air system is at least 65 psi (447 kPa), the trailer air supply valve knob must be pushed in (and should stay in) to charge the trailer air supply system and release the trailer spring parking brakes. Before disconnecting a trailer or when operating a vehicle without a trailer, the trailer air supply valve knob must be pulled out.
See Chapter 12 , Brake System, for complete brake operating instructions.

Trailer Brake Hand Control Valve Lever

The trailer brake lever (hand control valve) is used for applying the trailer brakes without applying the truck or tractor brakes. It is usually mounted on the right-hand control panel. See Fig. 5.12 . See Chapter 12 , Brake System, for complete brake operating instructions.
Fig. 5.12, Trailer Brake Lever