TM 9-2320-361-20 Table 2-3. Compressed Air and Brake System Troubleshooting (Contd). MALFUNCTION TEST OR lNSPECTION CORRECTIVE ACTION 15. FRONT WHEEL DRIVE DOES NOT ENGAGE (FRONT WHEEL DRIVE LOCK-IN SWITCH ENGAGED) Step 1. Start engine (TM 9-2320-361-10) and allow air pressure to build to normal operating pressure. Step 2. Inspect lines and hoses for air leaks. a. If air leaks are found, repair as required (para. 8-15). b. If no leaks are found, perform test 1. Test 1. Check front axle engagement air cylinder supply line (1) pressure. Step 1. Stop engine and open all draincocks (TM 9-2320-361-10) until brake system air pressure is vented. Step 2. Disconnect supply line (1) from air cylinder elbow (3). Step 3. Remove elbow (3) from air cylinder (2). Step 4. Install tee (5) on air cylinder (2). Step 5. Connect test gage (4) to tee (5) and connect supply line (1) to tee (5). Step 6. Start engine (TM 9-2320-361-10) and allow air pressure to build to normal operating pressure. Step 7. Place front wheel drive lock-in switch in ON position. Step 8. Check reading on test gage (4) and compare reading to instrument panel air pressure gage. a. b. NOTE Air pressure gage on instrument panel has a maximum pressure scale of 120 psi. If old governor has been replaced with new governor, air pressure may exceed maximum pressure reading on instrument panel gage. If reading is zero, replace front wheel drive lock-in switch (para. 6-4). If reading is lower than instrument panel gage, and air can be heard escaping from transfer case vent, notify your supervisor. Step 9. If air system is operating properly, notify your supervisor. 2-72