TM 5-5420-226-20-1 Symptom-57 DETAILED TROUBLESHOOTING PROCEDURE T SUPPORT SYSTEM -  VEHICLE LIGHTING (Continued) /Check basket-control panel accessories harness (CKT   38)  at  variable resistor lead   for  electrical power. Technician (Operator’s Station) Set   MASTER BATTERY switch OFF. Reconnect variable resistor lead  connector to  domelight, connector. Disconnect basket-control panel accessories harness connector (CKT 38) from variable resistor lead connector. Connect red   probe    of  meter to  basket-control panel ac- cessories harness connector and   black    probe    to  ground. Set   MASTER BATTERY switch ON. Check if  meter indicates 18  to   30   volts    dc. An, WI-F )!! TO   VEHICLE GROUND K CIRCUIT 38 Does    meter indicate 18  to   30  volts    dc? ( VARIABLE ‘ RESISTOR f Replace variable resistor assem- bly   (page 10-201). TA10728O 4-591