TM 9-4120-408-14
Table 4-4. Unit Troubleshooting Table (Continued).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. Air Conditioner Fails to Operate in Any Mode.
Step 1. Ensure all power connections to the control module, condenser assembly, and evaporator assembly are secure.
Inspect all external power cables for damage.
WARNING
Do not work on equipment with power connected. Electrocution hazard is present. Failure to obey this
warning may result in death or serious personal Injury.
Disconnect, clean connectors, and reconnect all connectors or connect power from a source supplying 28 vdc.
Step 2. Check to see if DC control circuit breaker in shelter is in the ON position.
a. Reset DC circuit breaker by placing it in the OFF and then in the ON position.
b. If the air conditioner will not operate, refer to applicable technical manual and test for defective
circuit breaker.
c. Replace defective circuit breaker.
Step 3. Check to see if mode selector switch (S1) on control module is in the HIGH COOL position.
a. Position mode selector switch in the HIGH COOL position.
b. If the air conditioner will not operate, test mode selector switch (S1) (paragraph 4-21).
Step 4. Refer to wiring diagrams (Figures H-1, H-2, and H-3) and inspect/test for defective wiring.
Repair or replace damaged or defective wiring as required.
2. Air Conditioner Suddenly Stops.
assembly are secure. Inspect all external power cables for damage.
4-8