Operation - Section 32 02/10 OM3237 Page 32-14 Operator Cab and Controls Cab air conditioner/heater vents (7, Figure 32-10) are spherically mounted and may be directed by the oper- ator to provide the most comfortable cabin air flow. Cab Air Conditioner/Heater Vents The wheel brake lock is used at the shovel and the dump only to hold the truck in position. DO NOT use this switch to stop the truck, unless the foot-operated treadle valve does not work. Use of this switch applies the rear service brakes with unmodulated pressure! DO NOT use the brake lock for parking because when the engine is stopped, hydraulic pressure will dissipate, allowing the brakes to release!
Engine Cold Weather Starting Aid Switch Optional engine cold weather starting aid switch (8, Figure 32-10) is spring-loaded to the OFF position. Use only when the ambient temperature is below 10°C (50°F). When the switch is held in the ON position, ether is injected into the engine intake manifold to aid the engine starting in cold weather. For additional information, refer to Section 30, Engine Start-Up. Rotating Beacon Light Switch Press rotating beacon light switch (9, Figure 32-10) to the ON position to activate the rotat- ing beacon. This is an optional feature. Parking Brake Switch Parking brake switch (13, Figure 32-10) is spring-applied and hydraulically released.
It is designed to hold the truck stationary when the engine is shut off and the key switch is turned OFF. The truck must be completely stopped before applying the parking brake, or damage may occur to the parking brake. To apply the parking brake, press the rocker switch toward the ON symbol. To release the parking brake, press the rocker switch toward the OFF symbol. When the key switch is ON and the parking brake switch is applied, parking brake indicator light (A3, overhead panel) will be illuminated. Heated Mirror Switch Press heated mirror switch (10, Figure 32-10) to activate the heat- ing element in the mirrors. This is an optional feature.
Wheel Brake Lock Switch Wheel brake lock switch (12, Figure 32- 10) must only be used when the engine is on. Use this function during dumping and loading. The brake lock switch actu- ates the hydraulic brake system, which locks the rear wheel service brakes only. When approaching the shovel or dump area, stop the truck using the service brake pedal. When the truck is completely stopped and in the loading position, apply the brake lock by pressing the rocker switch toward the ON symbol. To release, press the rocker switch toward the OFF symbol. NOTE: DO NOT use the parking brake at the shovel or dump.
With the key switch ON and the engine on, sudden shock caused by loading or dumping could cause the system's motion sensor to release the park brake.