TM-9-2320-279-20-1

M977 SERIES, 8x8 HEAVY EXPANDED MOBILITY TACTICAL TRUCKS (HEMTT)

TECHNICAL MANUAL; MAINTENANCE INSTRUCTIONS; ORGANIZATIONAL MAINTENANCE, VOLUME 1 OF 3

TM-9-2320-279-20-1 - Page 344 of 985

TM 9-2320-279 -20-1

Troubleshooting Malfunctions (Cent)

Table 2-9. Troubleshooting (Cent)

Malfunction

Test or Inspection

Corrective Action

ARCTIC HEATER KIT

1.

COOIANT PUMP FAILS TO OPERATE (INDICATOR LIGHT DOES NOT COME ON).

h

.

*

.

WIRE

NO. 1082

SWITCH

1

TA500537

Step 1. Remove heater compartment cover (para 20-2). Check for loose electrical connections at

coolant pump sw”tch and circuit breaker connections.

Tighten loose connections.

Step 2. Check for defective circuit breaker No. 4 (fig. 2-2), Test voltage across circuit

breaker No. 4.

If 24 vdc is present, go to Step 3.

If 24 vdc is not present, replace circuit breaker No. 4 (para 7-43)

Step 3. Check for voltage at terminal No. 1 of coolant pump switch. Place positive (+) probe on terminal

No. 1. Place negative (-) probe on known good ground.

If 24 vdc is present, go to Step 4.

If 24 vdc is not present, repair or replace wire No. 1082.

Step 4. Check for voltage at terminal No. 2 of coolant pump switch. With switch in ON position, place

positive (+) probe on terminal No. 2. Place negative (-) probe on known good ground.

If 24 vdc is present, go to Step 5.

If there is no voltage, replace coolant pump switch (para 20-2).

Step 5. If problem has not been solved, noti~ the supervisor.

Change

2

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