OM3216 3/10 Operator Cab and Controls - Section 32 Page 32-15 1. Depressing the top of the switch selects the OFF/ AUTO position which is used for enhanced truck operation. When the AISS switch is in this position, the idle speed will be determined by two conditions: engine coolant temperature, and brake application. Auxiliary Brake Switch Auxiliary brake switch (6, Figure 32-9) is used to apply the auxiliary braking system. Depress the button to apply the auxiliary brake sys- tem. When the switch is ON, the red lamp will illumi- nate. Pull the switch out to disable the auxiliary brake sys- tem. The light will turn off. a.
Engine Coolant Temperature - If the engine coolant temperature is below 30°C (86°F), the engine controller will signal for 1000 rpm, regardless of other conditions. If the engine coolant temperature is above 30°C (86°F), the engine controller will signal for 650 rpm, except as follows: When the auxiliary brake switch is activated, full, unmodulated hydraulic brake pressure (or what- ever pressure remains, if the system is failing) is applied to all wheels. In addition, the parking brake is also applied. b. Brake Application - If both the parking brake and service brake are released (acceleration anticipated), the engine controller will signal for 1000 rpm, regardless of other conditions.
Do not apply the auxiliary brake switch when the truck is moving, except in an emergency. NOTE: An amber light will illuminate the switch when the OFF/AUTO position is selected. NOTE: This switch is for the manual activation of the auxiliary brake circuit by the operator. The auxiliary brake circuit will apply automatically if the hydraulic brake pressure decreases below a pre-set value. 2. Depressing the bottom of the switch selects the ON/LOW position. When the AISS switch is in this position, the engine controller will signal for 650 rpm, regardless of other conditions. ON/LOW position is used when fine control movements are needed, such as parking in confined spaces. NOTE:
A green light will illuminate the switch when the ON/LOW position is selected. In cold ambient conditions and when the engine is cold, the engine rpm will not increase above low idle speed until the engine controller deter- mines it is safe to do so. This time delay will vary from 30 seconds to 11 minutes, allowing the cool- ant and engine oil to warm. AISS control will not be available until the engine completes this warm-up cycle.