Operation - Section 3 OM3020.2 12/99 Page 3-14 Operator Cab and Controls STEERING WHEEL AND CONTROLS The steering wheel (1, Figure 3-2) will telescope “in” and “out” and adjust through a tilt angle to provide a comfortable wheel position for most operators. HORN BUTTON The horn (2, Figure 3-2) is actuated by pushing the button in the center of the steering wheel. Operation of the horn should be verified before moving the truck. Observe all local safety rules regarding the use of the horn as a warning signal device before starting engine and moving the vehicle.
TELESCOPE LOCK RING The Telescope Lock Ring (3, Figure 3-2) around the horn button locks/unlocks the telescoping function of the steering column. Rotating the ring (*) counter- clockwise (L.H. rotation), releases the column to move "in" or "out". Rotating the ring clockwise (R.H. rotation), locks the column in the adjusted position. FIGURE 3-2. STEERING WHEEL AND CONTROLS (*) DO NOT ROTATE RING MORE THAN 90° ! Electrical ground wire may be cut! DYNAMIC RETARDING Dynamic Retarding is a braking torque (not a brake) produced through electrical generation by the wheel- motors when the truck motion (momentum) is the propelling force.
For normal truck operation, Dynamic Retarding should be used to slow and control the speed of the truck. TILT WHEEL LEVER Adjust the tilt of the steering wheel by pulling the tilt adjustment lever (4, Figure 3-2) toward the steering wheel and moving the wheel to the desired angle. Releasing the lever will lock the wheel in the desired location. Dynamic Retarding is available in “Forward/Reverse” at all truck speeds above 0 mph/kph; however, as the truck speed slows below 3 mph (4.8 kph), the available retarding force may not be effective. Use the service brakes to bring the truck to a COMPLETE stop.
TURN SIGNAL / HEADLIGHT DIMMER The Turn Signal Lever (5, Figure 3-2) is used to activate turn signal lights and to select either high or low head- light beams. Dynamic Retarding will NOT hold a stationary truck on an incline; use the Parking Brake or Wheel Lock brake for this purpose. Move the lever upward to signal a turn to the right. Dynamic Retarding is available in “Neutral” only when truck speed is above 3 mph (4.8 kph). When dynamic retarding is in operation, the engine RPM will automatically go to an advance RPM retard speed setting (usually 900 - 1000 RPM*). An indicator in the top, center of the instrument panel will illuminate to indicate turn direction se- lected.
Refer to INSTRUMENT PANEL & INDICATOR LIGHTS. * NOTE: The exact engine speed in retarding may vary due to the temperature of certain components; this is controlled by the Propulsion System Controller . Move the lever downward to signal a turn to the left. Dynamic retarding will be applied automatically , if the speed of the truck obtains the maximum truck speed of 40 MPH (64 KPH). Any application of the Dynamic retarding system (automatic, retarder lever, or foot pedal) will cause an indicator light to illuminate in the overhead display panel (D3, Figure 3-7).
The Grade/Speed Chart (8, Figure 3-1) should always be followed to determine MAXIMUM safe truck speeds for descending various grades with a loaded truck. Moving the lever toward the steering wheel changes Headlight beam. When high beams are selected, the indicator in the top, center of the instru- ment panel will illuminate.