Table 1. Cab Heating, Air Conditioning, and 12 Volt Power Inverter Troubleshooting Procedures.
TEST OR INSPECTION
N OT E
1. Heater Does Not Blow
Warm When Tempera-
Always inspect the harness connectorsthat are involved in the circuit.
ture Control Panel Is Set
Poor connections can often be the cause of a problem in an electrical
On Maximum Heat
circuit. Verify that all connections in the circuit are clean and secure,
and that all connections are in good condition. If a problem with a con-
nection is found, correct the problem and verify that this diagnostic code
is Active before performing this procedure.
Perform open or short circuit test ateach harness connection to identify
correct harness to replace.
Perform this test only if condition is active.
Test Step 1. Check for Active Diag-
1. Connect MSD (WP 0006), select
Diagnostic Code Active - Trouble-
Trans/Chassis 120M and check
shoot diagnostic code first before pro-
for active diagnostic codes.
ceeding (WP 0010).
Diagnostic Code Not Active - Pro-
ceed to step 2.
2. Operate machine until engine
reaches normal operating temper-
ature (TM 5-3805-293-10).
a. Turn fan speed switch to
HVAC Blower Motor Turns ON - Pro-
maximum speed (TM 5-3805-
ceed to step 4.
293-10) and verify HVAC
HVAC Blower Motor Does Not Turn
blower motor turns on in each
ON In One Or More Speeds - Diag-
nose HVAC blower motor first. Refer
to HVAC Blower Motor Does Not Turn
On In One or More Speeds in this
b. Turn temperature control to
No Warm Air Exiting from Air Vents
the warmest setting and verify
- Proceed to Test Step 2.
warm air exiting from air
Warm Air From Air Vents - Heater
OK, Troubleshooting complete.