CHART 2-24. Control Unit Troubleshooting (Sheet 1 of 12)

TM 11-5820-670-30

2-26. TROUBLESHOOTING CHARTS. (CONT)

CHART 2-24

Control Unit Troubleshooting

(Sheet 1 of 12)

NOTE

Use the troubleshooting table to isolate and correct faults in the control unit. The

troubleshooting table is used in the following manner.

1. Go to malfunction item number referred to in performance test.

2. Perform test or inspection.

3. If corrective action is taken, repeat performance test.

4. If no corrective action is taken, go to next step.

5. Repeat test procedure. Do all steps in sequence.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. Control panel lamps do not light.

No test.

Replace panel light assembly (para 2-76).

2. Wrong indication on test meter ( + 27.5 vdc applied),

Check continuity between main connector J9101 pins E, D, and C and J9101 pins e, f,

Repair wiring or replace MODE SWITCH S9105 (para 2-81).

3. Blower motor does not run.

Check continuity between main connector J9101 pins q and v. (See FO-13.)

Repair wiring or replace MODE SWITCH S9105 (para 2-81).

4. Absence of 27.5 vdc at TP4504.

Check continuity between pins C, D, E, and DD of main connector J9101. (See FO-13.)

Repair wiring or replace MODE SWITCH S9105 (para 2-81).

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