DRAFT
TM 5-4210-249-13&P-1
0048
b.
Continuity Checks.
1.
Set the multimeter function/range switch to any ohm range.
NOTE
Some meters show "l+m", or simply "l" when function/range switch is set to an ohm
position.
2.
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).
3.
If the circuit being measured is connected to power, turn engine start switch OFF (TM 9-2320-347-10).
4.
Connect test lead to one end of the wire or circuit to be measured. Use the other test lead to trace the
circuit being measured. When continuity is established, an ohm symbol will appear in the upper left
corner of the digital display. If contact with the circuit is maintained long enough (about 1/4 second), the
"OL" display will disappear and the resistance value if the circuit will be displayed. A resistance value of
200 ohms or less indicates continuity is being measured.
5.
If your multimeter does not work in this manner, learn how it operates before performing troubleshooting.
c.
Voltage Checks.
The TFFT is equipped with 24 VDC circuits. However, a valid reading may vary from 22 to 28 VDC, depending on
the charge on the batteries. When the batteries are fully charged, 25.2 VDC can be measured on an open 24 VDC
circuit, and 29 VDC can be measured when the engine is running at 1000 rpm.
1.
Set the multimeter function/range switch to the desired volts position. If the magnitude of the voltage is
not known, set the switch to the highest range, then reduce range until a satisfactory reading is obtained.
If a DC-AC switch is present, make sure it is set to the DC position
2.
Connect red test lead to volt-ohm input connector and black lead to COM connector on multimeter.
3.
Connect the tests leads to the circuit being measured. Connecting the red lead to the positive (+)
connection and the black test lead to the negative (-) or ground connection.
4.
Turn on switches as indicated in test procedure, to apply power to circuit being measured.
5.
Read the voltage value on the digital display.
6.
If your meter does not work in this manner, learn how it operates before performing troubleshooting.
d.
General Wire Testing and Repair.
Troubleshooting for the TFFT electrical system isolates malfunctions down to specific faulty components, using
resistance, continuity, and voltage checks as noted above. When the troubleshooting isolates the malfunction to a
faulty wire, the wire harness may be repaired or some cases replaced at Field Level Maintenance. If the wire
harness cannot be repaired or replaced at Field Level Maintenance, notify your Supervisor.
Wire repair at Field Level Maintenance is limited to splicing and taping the faulty wire. Refer to
TM 9-2320-325-14&P for wire harness repair procedures.
END OF WORK PACKAGE
0048-2
