66 INSTRUMENTS AND CONTROLS 33. Mode Button (Basic Display Only) – This push button is located directly below the Basic Display. The push button is used to access, navigate, view and change information available in the Basic Display. Simply press and hold the push button in for a moment to navigate through the screens. A long press of the push button is used to clear trip data or inactive fault codes. For more information on this button, please refer to the V-MAC® IV Operator’s Guide, TS898. 34. Speedometer — Indicates road speed in miles and/or kilometers per hour. 35. Tachometer – Indicates engine speed in revolutions per minute (RPM). Tachometer readings should be used as a guide for shifting, as well as to prevent engine damage due to overspeed. 36. Air Application Gauge (If Equipped) – Indicates the air pressure being delivered to the service brake chambers in the tractor (and trailer, if equipped); OR Air Suspension Gauge (If Equipped) – Indicates the air pressure being delivered to the air suspension system (100 psi range). 37. Hand-Control Brake Lever – Pull down to activate the trailer brakes, or the rear axle brakes in the case of a platform truck.
WARNING The hand-control brake system must NOT be used for parking. Do NOT use to apply service brakes while vehicle is in motion. Do not leave the vehicle while hand-control brake is applied.
38. Front Rear Axle and 39. Rear Rear Axle Oil Temperature Gauges (If Equipped) – Indicate rear axle oil temperature.
CAUTION The maximum safe oil temperature for MACK rear axles is 121°C (250°F). Continued operation with oil above this temperature will cause rapid deterioration of the oil’s lubricating properties and is NOT recommended. Consult the vendor manual for non-MACK components.
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