Measurement Device Handling

Measurement device	Purpose	Handling method	Handling cautions
Test light	Use to facilitate search for open or short circuits	Install test light between terminal and ground in circuit to be measured If the circuit is normal, the light will be on	When making test lights, use only 12 V bulb (1.4 W or 3.4 W) or light emitting diodes (LEDs) If a bulb with a capacity higher than the specified capacity is used, it will burn out transistors, particularly in a control module.
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Jumper wire	Use to operate switches and relays in circuits optionally	Install jumper wire between terminals of switches and relays to be operated optionally	Do not connect directly between power supply line and ground If it is connected directly, it may burn out wiring harnesses or damage electrical parts
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Voltmeter	Use when checking for open or short circuits by voltage, or electrical signals by voltage	Set positive lead wire to voltage measurement location, negative lead wire to ground	Connect voltmeter in parallel to circuit Use range appropriate to voltage to be measured When setting positive lead wire to narrow terminal, wrap thin wire around lead wire to set
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Ohmmeter	Use for verifying open or short circuits using continuity condition continuity of switches, or sensor resistance NOTE: Ohmmeter indicates continuity condition by replacing current flow with resistance when constant voltage is applied to measurement part.	Perform zero reset	Always perform zero reset after changing measuring range To prevent the ohmmeter from burning out, make sure that the ignition is switched OFF and the negative battery terminal is disconnected before use.
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		Verify that power supply is not connected to circuit Set lead wire to inspection location
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Oscilloscope	Used for verifying control module input/output signal (wave pattern) condition	Follow directions in appropriate service information for measuring range and terminal	Follow oscilloscope instruction manual and measure
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Ammeter	Used to inspect the back-up current in the circuit Back-up current: The current that flows in the circuit even when the ignition is switched OFF.	Connect positive lead wire to terminal on power supply side, negative lead wire to terminal on ground side in series with circuit	Use range appropriate to current being measured Connect ammeter in series with circuit If ammeter is connected in parallel, it may burn out
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