TM 10-6640-239-13 4-14 Table 4-3  Troubleshooting - CONT MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 12. AIR COMPRESSOR MOTOR INOPERATIVE, POWER AVAILABLE TO MOTOR CONTROLLER. Step 1.    Check operation of controller, (See FO-1). Step 2.    Check operation of air pressure switch. Step 3.    If controller and pressure switch are operating properly, continue to troubleshoot per commercial manual. If failure cannot be corrected, replace the air compressor.  See paragraph 4-34. 13. LEAKS IN SYSTEM CAUSE COMPRESSOR TO CYCLE ON AND OFF. Step 1.    Check air system piping, tubing, and unions for leaks. If leaks are found, repair or replace the leaking item.  See paragraph 4-36. Step 2.    Check for leaking air system valves. Replace faulty valves.  See paragraph 4-36. 14. AIR PRESSURE SWITCH CAUSING COMPRESSOR TO CYCLE ON AND OFF. Adjust pressure switch.  Refer to commercial manual. If switch will not adjust to operate properly, replace the pressure switch.  See paragraph 4-35. 15. VACUUM PUMP MOTOR INOPERATIVE, POWER AVAILABLE TO MOTOR CONTROLLER. Step 1.    Check operation of controller. If controller does not operate, refer to paragraph 4-26. Step 2.    Troubleshoot per TM 10-4310-391-13&P. If failure cannot be corrected, replace the vacuum pump.  See paragraph 4-37. 16. VACUUM PRESSURE LOW DUE TO LEAKS IN SYSTEM. Step 1.    Check vacuum system piping, tubing, and unions for leaks. If leaks are found, repair or replace the leaking item.  See paragraph 4-37. 17. WATER PUMP INOPERATIVE, POWER AVAILABLE TO MOTOR CONTROLLER. Step 1.    Check operation of motor controller (See FO-1). Step 2.    Check operation of water pressure switch. Step 3.    If controller and pressure switch are operating properly, troubleshoot per TM 10-4320-321-13&P. If failure cannot be corrected, notify direct support maintenance. 18. WATER PRESSURE LOW DUE TO LEAKS IN SYSTEM. Check system for leaking piping, tubing, unions, valves, supply tank, surge tank, or pump. When leak is isolated, notify direct support maintenance.