TM 5-5420-226-20-1 Symptom-65 DETAILED TROUBLESHOOTING PROCEDURE T SUPPORT SYSTEM -   VEHICLE LIGHTING (Continued) ‘Check    front    accessory harness (CKT   20)   at  headlight base    harness to   headlight assembly that    does    not work,    for   electrical power. ~ Second Technician (Operator’s Station) l First l Set   MASTER BATTERY switch OFF. Technician (Front of   Vehicle) Connect headlight assembly to   headlight base harness connector. Second Technician (Front of   Crew Compartment) Disconnect connector (CKT 20)   of   front accessory harness from headlight base    harness, of   defective headlight. Connect red    probe of   meter to   front accessory harness (CKT 20)   connector and black probe to ground. Set   MASTER BATTERY switch ON. Check if   meter indicates 18   to   30   volts dc. Does    meter indicate 18  to   30   volts    dc? 1’^{.Repairheadlightbase    harness} (CKT    20)   (page 10-186). HEADLIGHT 0- n + 0 II Y^{TO   VEHICLEGROUND} BASE HARNESS ELECTRICAL CONNECTORS /’ CIRCUIT 20 * ... .EFT FRONT CREW -1   L&=&&&’/ COMPARTMENT > ‘MA b--c=” \’ !!-- )1 TO ( L N YES No RIGHT FRONT CREW COMPARTMENT ) l   Inspect front    accessory harness for   bent/broken connector contact or   loose CKT    20   wire    at   rear   of connector. l   Repair    connector if  defective (page 10-298). l   If  connector is  not defective, notify support maintenance of   defective front accessory harness. l   Connect front    accessory harness to   headlight base harness. I J CONTACT TA1( i29 4-640