TM 9-4120-402-14
Table 4-3. UNIT TROUBLESHOOTING - continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
6. REDUCED HEATING CAPACITY. - continued
Step 8. Check individual heaters.
Test heaters. (See paragraph 4-44.) Replace defective heaters.
7. NO HEAT IN HEAT MODE.
WARNING
Disconnect input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
CAUTION
Use disconnect switch (NOT POWER CABLE) to disconnect power to unit.
Damage to cable connector pins will result if cable is used.
Step 1. Check for loose or damaged electrical connectors, or damaged wires in wiring harnesses.
Tighten or replace loose or damaged connectors, or replace damaged wires
Step 2.. Check operation of heater relay.
Test relay. (See paragraph 4-41.) Replace relay if defective.
Step 3. Check operation of potentiometer TEMPERATURE control.
Test potentiometer TEMPERATURE control. (See paragraph 4-29.) Replace cotnol if defective.
r
Step 4. Check operation of MODE selector rotary switch.
Test switch. (See paragraph 4-30.) Replace switch if defective.
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