TM 5-5420-226-20-1 ( Symptom-66 DETAILED TROUBLESHOOTING PROCEDURE SUPPORT SYSTEM -  VEHICLE LIGHTING T (Continued) Check   front   accessory harness    connector (CKT   21)  at bulkhead disconnect for   electrical power. Second Technician (Operator’s Station) l   Set   MASTER BATTERY switch OFF. First Technician (Rear Grille Doors) l   Connect    rear   accessory    harness   connector (CKT 21)  to left   taillamp assembly. First and    Second Technicians (Rear Grille Doors) l   Install    transmission shroud (page    9-6). First Technician (Commander’s Station) l   Displace front accessory harness connector (CKT 21) from    bulkhead disconnect (page 10-269). l   Conn;ct red   probe    of  meter to  contact A   (CKT 21)   of front accessory harness connector at   bulkhead disconnect, and   black    probe to   ground. Second Technician (Operator’s Station) l   Set   MASTER BATTERY switch ON. First    Technician (Commander’s Station) l   Check    if  meter   indicates 18  to   30  volts    dc. Does    meter indicate 18  to   30   volts    dc? m T o- + 0 TO   VEHICLE GROUND BULKHEAD ELECTRICAL ( FOR CLARITY QUADRANT ASSFMRI IFS NOT SHOWN } .. --—.-    .--. —-   ----- ---- l   Inspect rear   accessory harness for   bent/broken connector contacts or   loose CKT   21  wire    at   rear   of connectors. . l   Repair   connectors if defective. (page 10-298). l   If   connectors are   not defective, notify support maintenance of   a  defective rear   accessory harness. l   Install    front    accessory harness connector at bulkhead disconnect (page 10-270). TA   1,07332 4-643