TM-9-2320-285-24-2
TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1
TECHNICAL MANUAL; ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL
OCTOBER 1985
TM-9-2320-285-24-2 - Page 405 of 698
TM 9-2320-285-24-2
Section VII.
ACCESSORIES MAINTENANCE
This section contains the information you will need to maintain the cab heater.
It gives you instructions on how to troubleshoot problems and repair or replace the components that are
within the scope of direct support maintenance.
Para
Troubleshooting Symptom Index .
..................................................................................................
3-36
Heater Troubleshooting .
................................................................................................................
3-37
Heater Maintenance .
.....................................................................................................................
3-38
3-36.
TROUBLESHOOTING SYMPTOM INDEX
Para/Malfunction
Page
HEATER
Cab heater doesn’t heat cab .
............................................................................................
3-37/1
3-399
Fresh air door will not open or close .
................................................................................
3-37/2
3-400
Windshield will not defrost .
................................................................................................
3-37/3
3-400
3-37.
HEATER TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1.
CAB HEATER DOESN’T HEAT CAB
Step 1.
Remove motor (para 3-38).
Connect 12 Vdc power source to motor electrical leads.
Check if motor shaft rotates.
a. If motor shaft does not rotate, replace motor (para 3-38).
b. If motor shaft rotates, proceed to step 2 below.
Step 2.
Check heater core for leaks, cracks, distortion, or obstructions.
a. If heater core is leaking, cracked, or distorted, replace (para 3-38); if obstructed, clean (para 3-38).
b. If heater core is not leaking, cracked, distorted, or obstructed, proceed to step 3 below.
Step 3.
Check blower wheel for cracks, distortion, obstructions.
Check if setscrew is loose or missing.
a. If obstructions are found, remove; if blower wheel is cracked, or distorted, replace (para 3-38).
b. If setscrew is loose or missing, replace (para 3-38).
3-399
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