TM 9-2320-260-20
Table 2-4. Electrical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test 3. Test low air pressure switch voltage output.
Step 1. Ensure air pressure is below 65 psi (448 kPa).
Step 2. Disconnect lead 85 from pin B of low air switch.
Step 3. Turn battery switch and ignition switch to ON position.
Step 4. Touch negative lead of multimeter to frame ground.
Step 5. Touch positive lead of multimeter to pin B of low air switch. Voltage should be present.
a. If voltage is not present, go to test 4.
b. If voltage is present, go to step 6.
Step 6. Disconnect lead 85 from low air pressure buzzer.
Step 7. Set multimeter to RX1 scale.
Step 8. Touch positive lead of multimeter to contact end of lead 85 at low air pressure switch.
Step 9. Touch negative lead of multimeter to contact end of lead 85 at low air pressure buzzer.
Continuity should be present.
a. If continuity is present, go to test 4.
b. Repair or replace lead if continuity is not present (para. 4-52).
Test 4. Test voltage into low air switch.
Step 1. Disconnect lead 85 at pin A of low air pressure switch.
Step 2. Set multimeter to a voltage range that will measure 24 volts.
Step 3. Turn battery switch to ON position.
Step 4. Turn ignition switch to RUN position.
Step 5. Ensure air pressure is below 65 psi (448 kPa).
Step 6. Touch negative lead of multimeter to frame ground.
Step 7. Touch positive lead of multimeter to contact end of lead 85.
a. If voltage is not present, repair or replace lead 85 (para. 4-52).
b. Replace low air pressure switch if voltage is present (para. 4-26).
END OF TESTING!
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