Continuity checks.

DRAFT

TB 9-2320-364-13&P-1

FIELD LEVEL TROUBLESHOOTING INTRODUCTION - Continued

(d) Connect test leads to the circuit being measured. When measuring high resistance, be careful not

to contact adjacent points, even if they are insulated. Some insulators have a relatively low

insulation resistance which can affect the resulting measurement.

(e) Read the resistance value on the digital display.

2. Continuity checks.

(a) Place the function/range switch in any ohm range.

NOTE

Some meters show "l+m", or simply "l" when functioning/range switch is in any ohm

position.

(b) Connect the red test lead to the volt-ohm connector and black lead to COM input connector on the

meter. When the test leads are separated or measuring an out-of-range resistance, the digital

display will indicate "OL" (Over Limit).

circuit. When continuity is established, an ohm symbol will appear in the upper left corner of the

digital display. If contact in the wire is maintained long enough (about 1/4 of a second), the OL

display will disappear and the resistance value of the wire or circuit will appear next to the symbol.

A resistance value of 200 ohms or less indicates continuity is being measured.

(d) If your multimeter does not work in this manner, learn how it operates before performing

troubleshooting.

3. Voltage measurements. The PLS truck is equipped with both 12 vdc and 24 vdc circuits.

Troubleshooting procedures will reference 12 vdc and 24 vdc measurements, however these values can

vary. When the batteries are fully charged, 12.6 vdc can be measured on an open 12 volt circuit and

14.5 vdc can be measured when the engine is running at 1000 rpm. When the batteries are fully

charged, 25.2 vdc can be measured on an open 24 volt circuit and 29 vdc can be measured when the

engine is running at 1000 rpm. The PLS AC system circuits are 24 vdc circuits.

(a) Connect the red test lead to the volt-ohm input connector and the black lead to the COM input on the

meter. If a DC-AC switch is present, make sure it is set to the DC position.

(b) Set the function/range switch to the desired volts position. If the magnitude of the voltage is not

known, set the switch to a range which will be able to read most voltages seen on the truck

(typically, a 200V range will do). Then reduce the range until a satisfactory reading is obtained.

color test lead tube used is given in parenthesis (red is volt-ohm connection and black is the COM

connection).

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