OPERATOR AND FIELD LEVEL MAINTENANCE
TROUBLESHOOTING INSTRUCTIONS INTRODUCTION
This chapter contains Operator and Field Level troubleshooting procedures to diagnose and correct the most
common malfunctions of the TFFT. Refer to TM 9-2320-325-14&P for M977 series vehicle troubleshooting.
Each troubleshooting procedure in this manual lists a malfunction, followed by tests or inspections, and the
corrective actions needed to correct the malfunction. This manual cannot list all malfunctions that may occur. Nor
can it list all test, inspections, and corrective actions needed to correct the malfunctions. If a malfunction is not
listed, or if listed corrective actions do not correct the malfunction, notify your Supervisor. See WP 0049 for an
index of Operator Level troubleshooting procedures, and WP 0050 for Field Level troubleshooting procedures.
Before beginning any troubleshooting procedure, read and understand the operating procedures listed in
Chapter 2 of this manual. Perform all applicable Preventive Maintenance Checks and Services (PMCS)
procedures for the M977A2 series vehicle (TM 9-2320-325-14&P) and the M1142 series vehicle WP 0186. Ensure
all system setup procedures are completed.
All steps in these troubleshooting procedures must be performed in the order listed, to ensure all system interlocks
are in the correct position for system operations.
Use proper sized test leads and ensure care is used when checking for resistance,
continuity, or voltage at connectors or damage to equipment may result.
is not known, set the switch to the highest range, then reduce range until a satisfactory reading is
Some meters show "l+m", or simply "l" when function/range switch is set to an ohm
Connect red test lead to volt-ohm input connector and black lead to COM connector on multimeter.
When the test leads are separated or measuring out-of-range resistance, the digital display will indicate
"OL" (Over Load).
If the circuit being measured is connected to power, turn engine start switch OFF (TM 9-2320-347-10).
Connect test leads to the circuit being measured. When measuring high resistance be careful not to
contact adjacent point, even if they are insulated. Some insulators have a relatively low insulation
resistance which can effect the resulting measurement.
Read the resistance value on the digital display.
If your meter does not work in this manner, learn how it operates before performing troubleshooting.
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