A voltmeter is usually used in many ways in the automotive repair field, its most basic function is to check for voltage at a particular component such as a battery, brake light or switch.
Step 1 - To check for voltage (12 volts) at a particular accessory switch the meter to the DC voltage setting.
Step 2 - Grasp both negative and positive leads and hold them against
the desired test point such as a terminal or wire, the meter will instantly give
a reading.
Step 3 - Start the engine and watch the meter rise in voltage as the alternator
starts producing voltage. Switching the voltmeter to AC voltage will test the alternator
diodes for leakage which will destroy a battery over time, voltage should be 0 in
this test.
Step 4 - Switching the meter over to ohms will test the internal winding
circuit of any electronically controlled device such as a relay, sensor, fuel injector
or motor.
Step 5 - If high resistance or an open circuit is present the unit has
failed. Switch the meter to mV to test milli volt generation from a sensor, such
as a crank angle sensor while the engine is cranking over.
Step 6 - A voltmeter works great for testing pulse voltage which is needed
for fuel injectors and ignition coils.
Voltmeter Set to DC VoltageSPONSORED LINKS
Voltmeter Test LeadsVoltmeter Alternator TestSet Meter to OhmsTest Fuel Injector
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