HYDRAULIC OIL COOLER FANS WILL NOT OPERATE. cont'd

TM 5-2420-224-20-1

Table 3-5. Troubleshooting (Cont)

Malfunction

Test or Inspection

Corrective Action

ELECTRICAL SYSTEM (CONT)

Disconnect connector A (1) and check for +24 VDC between wire 70 (2)

Step 1.

and ground.

If +24 VDC is not present, repair wiring 70 between

connector A and fuse box 1.

If +24 VDC is present, reconnect connector A and go to step 2.

Disconnect connector X (3) and check for +24 VDC between wire 70 (2)

Step 2.

and ground.

If +24 VDC is not present, repair wiring 70 between

connector X and connector A.

If +24 VDC is present, reconnect connector X and go to step 3.

Check for +24 VDC between wire 70 (2) and ground at hydraulic oil cooler

Step 3.

terminal board (4).

If +24 VDC is not present, repair wiring 70 between

connector X and hydraulic oil cooler.

If +24 VDC is present, go to step 4.

Check for continuity of black and red wires (5) between hydraulic oil cooler

Step 4.

terminal board (4) and hydraulic oil cooler thermal switches (6).

if there is no continuity, repair black or red wire between

hydraulic oil cooler thermal switches and hydraulic oil cooler

terminal board.

If there is continuity, go to step 5.

Check for continuity of black and red wires (7) between hydraulic oil cooler

Step 5.

terminal board (4) and fan motors (8).

If there is no continuity, repair black or red wire between fan

motors and hydraulic oil cooler terminal board.

If there is continuity, go to step 6.

Remove two screws (9) and two lock washers (10).

Step 6.

Disconnect red wires (11 and 12) and short them to wire 70 (2).

Step 7.

If fans do not operate, replace hydraulic oil cooler (page 4-722).

If fans operate, replace both hydraulic oil cooler thermal

switches (page 4-1 47).

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