OPERATOR STATION ON HAULTRUCK 789D

INTRODUCTION
The operator’s station for the 789D is similar to the 789C operator’s station. A standard cab, deluxe cab, or deluxe cold weather cab are available. Operator visibility has been enhanced with the Object Detection System. The operator can receive both audible and visual indications of detected objects. In addition, the operator’s right hand view is improved due to relocation of the air tank on the chassis.



The following operator’s station components are visible in this image:
* Air suspension seat with three-point operator restraint (1) .
* Secondary Brake Pedal (2) .
* Multifunction lever (3).
* Object Detection System monitor (4) .
* Adjustable Steering Wheel/Column (Tilt and Telescoping) (5) .
* Quad gage and tachometer (6) .
* Overhead switch panel (7) .
* Right dash switch panel (8).
* VIMS message center module and keypad (9) .
* Transmission shift lever (10) .
* HVAC controls (11) .
* Trainer seat (12) .

OPERATOR’SSTATIONCOMPONENTS

The 789D truck hoist system is electronically controlled the same as the 789C. The hoist control lever (arrow) activates the four positions of the hoist control valve. The four positions are: RAISE, HOLD, FLOAT, and LOWER.
A fifth position of the hoist valve is called the SNUB position. The operator does not have control over the SNUB position. When the body is lowered, just before the body contacts the frame, the Transmission/Chassis ECM signals the hoist solenoids to move the hoist valve spool to the SNUB position. In the SNUB position, the body float speed is reduced to prevent hard contact of the body with the frame.

The truck should normally be operated with the hoist lever in the FLOAT position. Traveling with the hoist in the FLOAT position will make sure the weight of the body is on the frame and body pads and not on the hoist cylinders. The hoist valve will actually be in the SNUB position.
If the transmission is in REVERSE when the body is being raised, the hoist lever sensor is used to shift the transmission to NEUTRAL. The transmission will remain in NEUTRAL until:
* the hoist lever is moved into the HOLD or FLOAT position; and .
* the shift lever has been cycled into and out of NEUTRAL..

NOTE: If the truck is started with the body raised and the hoist lever in FLOAT, the lever must be moved into HOLD and then FLOAT before the body will lower.

Identify indicators on center of front dash panel

Shown is the center of the front dash panel. Four dash indicators, the four-gauge cluster module, and the speedometer/tachometer module are visible.
The four dash indicators to the left of the four-gauge cluster module are (from top to bottom):
* Left turn .
* Body up: Lights when the body is up; Input is from the body position .
* sensor. Reverse: Lights when the shift lever switch is in REVERSE. .
* High beam .

The four systems monitored by the four-gauge cluster module are (top and bottom, left to right):
* Engine coolant temperature: Maximum operating temperature is 107°C (225°F).
* Brake oil temperature: Maximum operating temperature is 121°C (250°F).
* System air pressure: Minimum operating pressure is 450 kPa (65 psi).
* Fuel level: Minimum operating levels are 15% (Category 1) and 10%  (Category 2).

The three systems monitored by the speedometer/tachometer module are:
* Tachometer: Displays the engine speed in rpm. •
* Ground speed: Displayed in the left side of the three-digit display area and can be displayed in             miles per hour (mph) or kilometers per hour (km/h).

Actual gear: Displayed in the right side of the three-digit display area  and consists of two digits that show the actual transmission gear that is engaged. The left digit shows the actual gear (such as “1,” “2,” etc.). The right digit shows the direction selected (“F,” “N,” or “R”).

Identify controls on right side of dash

Located on the right side of the steering column is the manual retarder lever (1). The manual retarder lever is used to modulate engagement of the service brakes on all four wheels. The retarder system allows the machine to maintain a constant speed on long downgrades. The retarder will not apply all of the normal braking capacity.

On the right side of the dash are several rocker switches, the Vital Information Management System (VIMS) message center module (2), the VIMS keypad (3), the heating and air conditioning temperature knob (4), and the fan speed switch (5).
The rocker switches (6) on the right side of the dash control the following systems:

Top row (from left to right): 
* Throttle back-up: Raises the engine speed to 1300 rpm if the throttle sensor signal is invalid.
* ARC: Activates the Automatic Retarder Control (ARC) system.
* Brake release/hoist pilot: Used to release the parking brakes for towing and provide hoist pilot oil       to lower the body with a dead engine. The small latch must be pushed UP before the switch can be     pushed DOWN.
* TCS test: Tests the Traction Control System (TCS). Use this switch when turning in a tight circle         with the engine at LOW IDLE and the transmission in FIRST GEAR. The brakes should                     ENGAGE and RELEASE repeatedly. The test must be performed while turning in both directions       to complete the test.

Bottom row (from left to right):
* Panel Lights: Use this switch to DIM the panel lights.
* Idle shutdown timer switch.
* Air Conditioning: Use this switch to turn ON the air conditioner .
* Heated mirror switch .

The idle shutdown timer switch allows the engine to shutdown after a specific time period after the key start switch is turned off. The amount of idle time is programmed using Cat ET. The following conditions must be met to activate the idle shutdown timer:
* The idle shutdown timer switch is ON.
* The parking brake is ENGAGED.
* The retarder is OFF.
* The throttle pedal is RELEASED.
* The brake pedals are RELEASED.

The five dash indicators (7) to the left of the rocker switches are (from top to bottom):
* Right turn
* Action lamp: Lights when a Category 2, 2-S, or Category 3 Warning is active.
* Stairway Down (if equipped): ON when powered stairway is fully retracted.
* Retarder: Lights when the retarder is ENGAGED (Auto or Manual).
* Flashes rapidly when a fault in the ARC system is detected..
* TCS: Lights when the Traction Control System (TCS) is ENGAGED.

Identify components on floor of cab

Located on the floor of the cab are: 
* Secondary brake pedal (1): Used to modulate application of the parking brakes on all four wheels.
* Service brake pedal (2): Used to modulate engagement of the service brakes on all four wheels. For     more precise modulation of the service brakes, use the manual retarder lever on the right side of         the steering column.
* Throttle pedal (3): A throttle position sensor (4) is attached to the throttle pedal. The throttle               position sensor provides the throttle position input signals to the Engine ECM.

NOTE: The throttle position must be programmed to the 10 to 90% setting. The earlier trucks must be programmed to a 10 to 50% throttle position. The setting is changed in the Engine ECM configuration screen with Cat ET.

The Engine ECM provides an elevated engine idle speed of 1300 rpm when the engine coolant temperature is below 60°C (140°F). The rpm is gradually reduced to 1000 rpm between 60°C (140°F) and 71°C (160°F). When the temperature is above 71°C (160°F), the engine will idle at LOW IDLE (700 rpm).

Increasing the low idle speed helps prevent incomplete combustion and overcooling. To temporarily reduce the elevated idle speed, the operator can release the parking brake or depress the throttle momentarily, and the idle speed will decrease to LOW IDLE for 10 minutes.
The cab air filter (5) is located to the right of the throttle pedal.

Identify components on shift console, right of operator’s seat

To the right of the operator’s seat is the shift console. Located on the shift console are the transmission shift lever (1), the parking brake air valve (2), and the parking brake reset valve (3).
The 789D truck transmission has SIX speeds FORWARD and ONE speed REVERSE. The top gear limit and body up gear limit are programmable through the Transmission/Chassis ECM. The top gear limit can be changed from THIRD to SIXTH. The body up gear limit can be changed from FIRST to THIRD.

Identify overhead panel switches

Located in the overhead panel are several switches:
* Hazard lights (1)
* Headlights and parking/taillights (2)
* Fog lights (3)
* Access lights (4)
* Side and rear work lights (5)

 Identify fuse and circuit breaker panel.

Shown is the fuse, relay, and circuit breaker panel located behind the operator’s seat. The 789D trucks now use fuses and relays in addition to circuit breakers to protect the electrical circuits.
A 12 volt/5 amp power port (1) provides a power supply for 12 volt devices, such as a laptop computer.
A laptop computer with the VIMS software installed can be connected to the diagnostic connector (2) to obtain diagnostic and production information from the VIMS Electronic Control. A laptop computer with Cat ET software installed can be connected to the Cat Data Link connector (3) to obtain diagnostic information and perform programming functions on all the electronic controls.

Identify controls on right side of dash

VITALINFORMATIONMANAGEMENT SYSTEM (VIMS)
Shown is the Vital Information Management System (VIMS) message center module (1) and the keypad module (2).
The message center module consists of an alert indicator, a universal gauge, and a message display window. The alert indicator flashes when a Category 1, 2, 2-S, or 3 Warning is present.

The universal gauge displays active or logged data (machine) and maintenance (system) events. The universal gauge will also display the status of a sensor parameter selected for viewing by depressing the GAUGE key on the keypad. The message display window shows various types of text information to the operator, depending on the menu selected with the keypad. An active event will override most displays until acknowledged by depressing the OK Key.

The VIMS provides three Warning Categories. The first category requires only operator awareness. The second category states that the operation of the machine and the maintenance procedure of the machine must be changed. The third Warning Category states that the machine must be safely shut down immediately.

Warning Category 1 
For a Category 1 Warning, the alert indicator will flash. The universal gauge may display the parameter and a message will appear in the message display window. A Category 1 Warning alerts the operator that a machine system requires attention. The “OK” key on the keypad can be used to acknowledge the warning. Some warnings will be silenced for a predetermined period. After this time period, if the abnormal condition is still present, the warning will reappear.

Warning Category 2 
For a Category 2 Warning, the alert indicator and the action lamp will flash. The universal gauge may display the parameter and a message will appear in the message display window. A Category 2 warning alerts the operator that a change in machine operation is required to avoid possible damage to the indicated system. The “OK” key on the keypad can be used to acknowledge the warning. Some warnings will be silenced for a predetermined period. After this time period, if the abnormal condition is still present, the warning will reappear.

Warning Category 2-S 
For a Category 2-S Warning, the alert indicator and the action lamp will flash and a continuous action alarm will sound, which indicates a SEVERE Category 2 Warning. The universal gauge may display the parameter and a message will appear in the message display window. A Category 2-S Warning alerts the operator to immediately
change the operation of the machine to avoid possible damage to the indicated system. When the change in operation is made to an acceptable condition, the action alarm will turn off. warning

Category 3 
For a Category 3 Warning, the alert indicator and the action lamp will flash and the action alarm will sound intermittently. The universal gauge may display the parameter and a message will appear in the message display window. A Category 3 Warning alerts the operator that the machine must be safely shut down immediately to avoid damage to the machine or prevent personal injury. Some Category 3 Warnings cannot be stopped by pressing the “OK” key.

Explain operation of ViMS interface modules

The previous VIMS main module and the two VIMS interface modules have been replaced by the VIMS ECM (1). The VIMS ECM receives input signals from many switches and sensors (9) located on the machine. The VIMS ECM also communicates with other ECMs on the machine. The VIMS provides the operator and the service technician with a complete look at the current and past conditions of all the systems on the truck.

The TPMS is an integral part of the VIMS. Access to the TPMS information is provided through the VIMS message center module (2) and keypad module (3), or through a laptop computer with the VIMSpc (4) software installed. The VIMS monitors all the systems on the truck, but Cat ET (5) is used for programming, running diagnostic tests, and retrieving logged information from the Engine ECM (6), the Transmission/Chassis ECM (7), and the Brake ECM (8). VIMS communicates with the ECMs and Cat ET over the Cat Data Link (17).

The VIMS ECM communicates with the keypad module over the Keypad Data
Link (16), and with the speedometer/tachometer module (13) and gauge cluster module (14) over the Display Data Link (15). The VIMS ECM also sends output signals to the action lamp (11) and the action alarm (10). An RS-232 service connector is used to connect a laptop computer with VIMSpc software to upload new source and configuration files, view real time data, or download logged information from the VIMS. The VIMS service key start switch (18) must be in the ON position before the laptop computer with VIMS software will communicate with the VIMS.

When the key start switch is turned ON, the VIMS runs through a self test. During the self test, the blue service lamp (12) will flash three times if any logged events are stored in the VIMS ECM and once if no logged events are stored. During normal operation, the service lamp will turn ON to notify the technician that the VIMS has an active data (machine) or maintenance (system) event. The service lamp flashes to indicate when an event is considered abusive to the machine.

Identify Brake, Transmission/ Chassis, and ViMS ECMs

The Brake ECM (1), the Transmission/Chassis ECM (2), and the VIMS ECM (3) are located in the rear of the cab.
The Brake ECM controls the Automatic Retarder Control (ARC) system, the Traction Control System (TCS), and rear axle cooling.

The Transmission/Chassis ECM controls the shifting of the transmission, torque converter lockup, the hoist system, the neutral-start feature, power train filter and temperature monitoring, and the automatic lubrication feature.
All these electronic controls, along with the Engine ECM, communicate with each other on the Cat Data Link. All the information from these controls can be accessed through the VIMS message center or a laptop computer with Cat ET or VIMSpc software.

Some of the operations that can be performed with a laptop computer with VIMSpc installed are:
* View real time data (similar to the status menu of Cat ET).
* View payload data .
* Start and stop a data logger.
* Calibrate the payload system .
*  Upload source and configuration files (similar to flash programming • other ECMs with Cat ET)
* Assign serial and equipment numbers
* Reset onboard date, time, and hourmeter .
* Download event list, data logger, event recorder, payload data, trend data,  cumulative data, and           histogram data


789D Off-Highway Truck Operator’s Station Post-Assessment
Instructions: Select the correct answer(s) for each question.
1. The parking brakes are engaged when ________________________.
    a. the parking brake switch is pressed
    b. the transmission shift lever is moved to PARK
    c. the hoist control lever is moved to FLOAT
    d. the service brake pedal is depressed
2. The ET connector is located __________.
    a. inside a box, which is installed near the front of the engine
    b. behind the companion seat
    c. [behind the operator’s seat]
    d. in the engine compartment
3. The VIMS ECM communicates with which of the following: (select all that apply)
    a. [Keypad module]
    b. [Engine ECM]
    c. [Transmission/Chassis ECM]
    d. [Brake ECM]
4. If the ARC switch is in the ON position and on a downgrade, the machine is slowed down using the __________.
   a. retarder lever
   b. front and rear mechanical brakes
   c. [engine braking system]
   d. front brakes
5. The engine idle shutdown function is activated by the operator by moving __
   a. the key start switch to OFF
   b. the secondary brake pedal to 10%
  c. [the idle shutdown timer switch to ON]
  d. the throttle back-up switch to OFF