. OPERATION MACHINE OPERATIONS AND CONTROLS OPERATION MACHINE OPERATIONS AND CONTROLS 4) If For details of the method of checking the maintenance interval, see "Maintenance Switch (PAGE 3-22)" in the Detailed controls and gauges. 3 - 78 If the lamp hydraulic (15) st oil temperature ays lighted up gauge red, goes out perform and caution inspection immediately fo r the item which is lighted up red. time up f seconds . Press maintenance switch (17), check the item, then perform m aintenance immediately.