TM 5-3810-288-12
Table 3-6. Heater Trouble Shooting Chart
Trouble
Probable cause
Possible remedy
Heater motor inoperative
1. Wiring faulty.
1. Repair or replace wiring.
2. Heater motor faulty.
2. Replace heater motor (fig. 3-65).
Heater delivers cold air
1. Engine thermostat stuck.
1. Replace engine thermostat (para
2. Heater hose blocked.
2. Replace or repair blocked hose.
3. Air lock in water line to heater.
3. Disconnect heater hose and drain
line until air lock is bled from
system.
4. Dirt on outside of coil.
4. Remove cover and clean outside
of coil.
5. Sediment in inside of coil.
5. Remove input and output hoses
and flush coil with suitable
solvent
Heater does not deliver air
1. Heater motor inoperative.
1. See above.
2. Fan loose on electric motor shaft.
2. Remove motor and tighten fan on
motor shaft
Heater leaks
Broken coil.
Replace coil.
b. Hoses, Fittings, and Tubing.
(2) Replacement. Close the shutoff valve at the
hydraulic reservoir shown in figure 3-68. Then, refer to
damaged hydraulic hose, fitting, or tube.
loose fitting, hose, or tube which is causing the hydraulic
system to leak. Be sure to wipe up any spilled hydraulic
Note. Always cap or plug each end of the hose or
fluid. If any brake or clutch lining is touched by the spilled
fitting when a piece has been removed, to prevent dirt
hydraulic fluid, refer to the appropriate paragraph and
from entering the hydraulic system and to prevent the
replace the brake or clutch lining. Hydraulic fluid is a
loss of unnecessary amounts of hydraulic fluid. Refill
lubricant, and will cause otherwise serviceable brake or
the hydraulic reservoir and bleed the system as
clutch linings to sip.
described in the following, when the damaged item has
been replaced.
3-77
