TM 9-2320-361-20 Table 2-4. Electrical Troubleshooting (Contd). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 22. FRONT BLACKOUT MARKER LAMP DOES NOT LIGHT Test 1. Test battery voltage at front marker light. Step 1. Step 2. Step 3. Step 4. Turn main light switch to OFF position. Disconnect lead 20 at rear of front composite light on side of vehicle where light does not light. Turn main light switch lever to BLACKOUT MARKER or BLACKOUT DRIVE position. Check for battery voltage at contact end of lead 20. a. If battery voltage is present, go to test 2. b. If battery voltage is not present, go to malfunction 17, test 3, and check front wiring harness pin E. Test 2. Test continuity of filament in blackout marker lamp. Step 1. Set multimeter to RX1 scale. Check continuity between frame ground and lead 20 attached to rear of blackout marker lamp. Step 2. If continuity is not present: a. Replace blackout marker lamp (para. 4-46). b. If continuity is present, check for corroded contacts at lamp and at lead 20 connection to front wiring harness. Reconnect lead 20. 2-107