TM 9-2320-272-24-1
Table 2-4. Compressed Air and Brake System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test 6. Check for air pressure at front wheel drive lock-in switch (2).
Step 1. Disconnect air line (1) from front wheel drive lock-in switch (2) and connect test
gauge to front wheel drive lock-in switch (2).
Step 2. With engine at idle, ensure transfer case shift lever is in HIGH position, and engage
front wheel drive lock-in switch.
Step 3. Observe test gauge.
a. If air pressure is not indicated, replace front wheel drive lock-in switch (2)
b. If air pressure is present, repair or replace air line (1).
Test 7. Check for air pressure from actuator valve air delivery line (4) at transfer case (supply
pressure normal).
Step 1. Disconnect air delivery line (4) and connect test gauge to air line (4).
Step 2. With engine at idle, place transfer case shift lever in LOW position.
Step 3. Observe test gauge.
a. If air delivery pressure is normal, notify DS maintenance that transfer case does not
engage front wheel drive.
b. If air delivery pressure is below normal, perform test 8.
c. Stop engine, drain air, remove test gauge, and connect delivery line (4).
Test 8. Check air pressure at actuator valve (3) (supply pressure normal).
Step 1. Disconnect air delivery line (4) at actuator valve (3) and connect test gauge to air
delivery port (5).
Step 2. With engine at idle, place transfer case shift lever in LOW position.
Step 3. Observe test gauge.
a. If air delivery pressure is normal, repair or replace blocked air delivery line (4).
(TM 9-243).
b. If air delivery pressure is below normal, actuator valve (3) is defective. Notify DS
maintenance.
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