TM 10-6640-239-13 4-13 Table 4-3  Troubleshooting - CONT MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 5. A GROUP OF CEILING LIGHTS FAIL TO ILLUMINATE, ALL OTHER CEILING LIGHTS ILLUMINATED. Step 1.    Check that power is available to appropriate wall light switch. a.   If power is available, replace switch.  Refer to paragraph 4-22. b.   If power is not available, proceed to Step 2. Step 2.    Check and reset appropriate circuit breaker. If power is still not available, replace circuit breaker.  See paragraph 4-18. 6. DOOR INTERLOCK SWITCH INOPERATIVE. Step 1.    Check switch electrical connection. Step 2.    Adjust switch. If switch is inoperative, replace the door interlock switch.  See paragraph 4-23. 7. CONVENIENCE OUTLET, RECEPTACLE, INOPERATIVE. Step 1.    Check that power is available at outlet. a.   If power is available, replace outlet.  See paragraph 4-24. b.   If power is not available, proceed to Step 2. Step 2.    Check and reset appropriate circuit breaker. If power is still not available, replace circuit breaker.  See paragraph 4-18. 8. ECU REMOTE CONTROL UNIT INOPERATIVE, POWER AVAILABLE. Troubleshoot per TM 5-4120-388-14.  If necessary, replace faulty remote control unit.  See paragraph 4-25. 9. ENVIRONMENTAL CONTROL UNIT INOPERATIVE, POWER AVAILABLE. Troubleshoot per TM 5-4120-388-14. 10. PURGE DAMPER, INTAKE, EXHAUST, OR ECU INTAKE, INOPERATIVE. Step 1.    Check that damper operating linkage is not loose or broken. Repair linkage.  See paragraphs 4-28 thru paragraph 4-33 for specific motor. Step 2.    Check that electrical power is available to damper motor. If power available to motor, replace motor.  See paragraphs 4-28 thru paragraph 4-33 for specific motor. 11. PURGE DOOR LIMIT SWITCH INOPERATIVE. Step 1.    Check for loose electrical connections. Step 2.    Check that power is available to switch. If power is available, replace switch.  See paragraph 4-28.