GreenWorks CU800 - Continuity Test; Testing for a Short with Self-Powered Test Light or Ohmmeter

GENERAL INFORMATION CU800 Service Manual
51
Because resistance causes voltage to drop. A voltmeter is used to measure voltage drop
when current is running through the circuit. If the circuit has no resistance. There is no voltage
drop so the voltmeter indicates 0 volts. The greater the resistance in a circuit. The greater the
voltage drop reading.
To perform a voltage drop:
1. Connect the positive meter test leads to the electrical source (where electricity is coming from).
2. Connect the voltmeter negative test leads to the electrical load (where the electricity is going).
3. If necessary, activate the component(s) in the circuit. For example. If checking the voltage in the
starter circuit, it would be necessary to push the starter button.
4. Read the voltage drop (difference in voltage between the source and destination) on the
voltmeter. Note the following:
a. The voltmeter should indicate 0 volts. If there is a drop of 0.5 volts or more. There is a problem
within the circuit. A voltage drop reading of 12 volts indicates an open in the circuit.
b. A voltage drop of 1 or more volts indicates that a circuit has excessive resistance.
c. For example, consider a starting problem where the battery is fully charged but the starter motor
turns over slowly. Voltage drop would be the difference in the voltage at the batter (source) and the
voltage at the starter (destination) as the engine is being started (current is flowing through the
batter cables). A corroded battery cable would cause a high voltage drop (high resistance) and slow
engine cranking.
d. Common sources of voltage drop are loose or contaminated connectors and poor ground
connections.
1.19.10.3 Continuity Test
A continuity test is used to determine the integrity of a circuit, wire or component. A circuit has
continuity if it forms a complete circuit, that is, if there are no opens in either the electrical wires or
components within the circuit. A circuit with an open. On the other hand, has no continuity.
This type of test can be performed with a self-powered test light or an ohmmeter. An ohmmeter
gives the best results. If using an analog ohmmeter, calibrate the meter by touching the leads together
and turning the calibration knob until the meter reads zero.
1. Disconnect the negative battery cable.
2. Attach one test lead (test light or ohmmeter) to one end of the part of the circuit to be tested.
3. Attach the other test leads to the other end of the part or the circuit to be tested.
4. The self-powered test lead comes on if there is continuity. An ohmmeter reads 0 or very low
resistance if there is continuity. A reading of infinite resistance if there is continuity. A reading of
infinite resistance indicates no continuity, the circuit is open.
1.19.10.4 Testing for A Short with Self-Powered Test Light or Ohmmeter
1. Disconnect the negative battery cable.
2. Remove the blown fuse.
3. Connect one test lead of the test light or ohmmeter to the load side (battery side) of the fuse
terminal in the starter relay.
4. Connect the other test leads to a good ground (bare metal). Make sure the part used for a ground
is not insulated with a rubber gasket or rubber grommet.
5. With the self-powered test light or ohmmeter attached to the fuse terminal and ground, wiggle the