OM3241 Operation - Section 32 Operator Cab and Controls Page 32-7 Override Switch Override switch (7, Figure 32-6) is spring-loaded to the OFF posi- tion. When pushed inward and held, this switch has several uses. Retard Speed Control (RSC) Switch Retard speed control switch (6, Figure 32-6) turns the system off or on. Push the knob in to turn the system off, and pull the knob out to turn the system on. 1. The override switch permits the operator to move the truck forward when the selector switch is in FORWARD, the dump body is raised, and the brakes are released. . Only use the override switch in emergency situa- tions. 2.
If the operator stops the truck on an uphill incline, the override switch can be used to set up the forward propulsion while the brakes are applied. As soon as the forward propulsion is felt, release the brakes. As the truck begins to move forward, release the override switch. Retard Speed Control (RSC) Dial RSC dial (5, Figure 32-6) allows the operator to vary the downhill truck speed that the retard speed control system will maintain when descending a grade. When the dial is rotated counterclockwise toward the turtle symbol, the truck will descend a grade at lower speeds. 3. The override switch deactivates the retard pedal function when the speed of the truck is below 5 kph (3 mph). 4.
The override switch is also used to reset an elec- tric system fault when indicated by the red warn- ing light. Refer to Overhead Warning/Status Indicator Light Panel in this section. When the dial is rotated clockwise toward the rabbit symbol, the truck speed will increase. The throttle pedal position will override the RSC set- ting. If the operator depresses the throttle pedal to increase the truck speed, dynamic retarding will not activate unless the truck overspeed setting is reached, or the retard pedal is used. When the throt- tle pedal is released, dynamic retarding will activate at the RSC preset speed. The RSC control will main- tain the truck speed at the preset limit.
To adjust the RSC control, pull switch (11) to the ON position. Start with dial (12) rotated toward the fastest speed while driving the truck at the desired maximum speed. Relax the throttle pedal to let the truck coast, and turn the RSC dial slowly counterclockwise until dynamic retarding is activated. Dynamic retarding will now be activated automatically anytime the set speed is reached, the RSC switch is ON, and the throttle pedal is released. IN OFF OUT ON