TM 10-6640-239-13 3-5 Table 3-2.  Troubleshooting - continued MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 3. CEILING LIGHTS DS1, DS2, DS3, DS4, AND DS5 FAIL TO ILLUMINATE. Step 1.    Check operation of forward door, center switch and rear door, center switch. Step 2.    Check and reset circuit breaker A1CB11. If lights still fail to operate, notify unit maintenance. 4. CEILING LIGHTS DS6, DS8, DS9, AND DS10 FAIL TO ILLUMINATE. Step 1.    Check operation of forward door, forward switch and rear door, roadside switch. Step 2.    Check and reset circuit breaker A1CB9. If lights still fail to operate, notify unit maintenance. 5. CEILING LIGHTS DS7, DS11, DS12, AND DS13 FAIL TO ILLUMINATE. Step 1.    Check operation of forward door, rear switch and rear door, curbside switch. Step 2.    Check and reset circuit breaker A1CB13. If lights still fail to operate, notify unit maintenance. 6. GROUP OF WHITE CEILING LIGHTS FAIL TO ILLUMINATE, GROUP BLACKOUT LIGHTS ARE ON. Check operation of the group’s door interlock switches. a.    Ensure door interlock switches are closed.  White lights should illuminate. b.    If white light does not illuminate, notify unit maintenance. 7. MECHANICAL ROOM CEILING LIGHTS DS14 AND DS15 FAIL TO ILLUMINATE. Step 1.    Check operation of mechanical room door switch. Step 2.    Check and reset circuit breaker A15CB10. If lights still fail to illuminate, notify unit maintenance. 8. WHEN ONE OF THE PETROLEUM LABORATORY DOORS IS OPENED, A GROUP OF WHITE LIGHTS FAIL TO GO OFF AND THE GROUP’S BLACKOUT LIGHTS FAIL TO ILLUMINATE. Check operation of the light group’s door interlock switch. a.    Adjust door interlock switch. b.    If lights still fail to operate, notify unit maintenance. 9. EMERGENCY LIGHT DS7 OR DS13 FAIL TO ILLUMINATE WHEN A POWER FAILURE OCCURS. Check operation of forward or rear door emergency light switches. a.    Ensure switch is in the ON position. b.    If emergency light still fails to operate, notify unit maintenance.