TM 5-2420-231-23-1
0030
Table 1. Heating and A/C Troubleshooting Procedures - Continued.
030
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. Heater Does Not Blow
3. Replace thermostat (WP 0130).
Warm Air When
4. Start and operate machine until
Temperature Control Is
engine reaches normal operating
Set to Maximum Heat -
temperature (TM 5-2420-231-10).
Continued
5. Rotate heater temperature control
No Warm Air Exits From Air Vents -
to the warmest setting (TM 5-
Proceed to step 6.
2420-231-10) and verify that warm
Warm Air Exits From Air Vents -
air is exiting from air vents.
Proceed to Test Step 6.
6. Remove cab floor cover plate (WP
0306).
7. Inspect heater inlet hose (Figure
Heater Hose and Clamps OK -
10, Item 2) and heater outlet hose
Proceed to step 8.
(Figure 10, Item 3) for Class III
Class III Leaks Present at Heater Inlet
leaks, loose or broken clamps (Fig-
or Heater Outlet Hose - Replace
ure 10, Items 1 and 4), cracks,
clamps. If hose continues to leak,
kinks, sharp bends, collapsed
replace heater hose (WP 0354).
areas, or restrictions.
Proceed to Test Step 6.
Heater Hose Clamp Loose - Replace
clamp (WP 0354).
Proceed to Test Step 6.
Heater Hose Cracked, Kinked,
Sharply Bent, Collapsed, or
Restricted - Straighten or replace
heater hose (WP 0354).
Proceed to Test Step 6.
0030-12
