GM Service Manual Online
For 1990-2009 cars only

Notice: Refer to Test Probe Notice in the Preface section.


    Object Number: 1940045  Size: SH
  1. Disconnect the electrical harness connector for the circuit being tested, if necessary.
  2. Enable the circuit and/or system being tested. Use the following methods:
  3. • Turn the ignition to the ON position, with the engine OFF.
    • Turn the engine to the ON position.
    • Turn the circuit and/or system to the ON position with a scan tool in Output Controls.
    • Turn the switch for the circuit and/or system being tested to the ON position.
  4. Select the V (AC) or V (DC) position (5) on the Digital Multimeter (4) depending on the circuit to be tested.
  5. Connect the positive lead (2) of the Digital Multimeter (4) to the point of the circuit to be tested.
  6. Connect the negative lead (1) of the Digital Multimeter to a known good ground.
  7. The Digital Multimeter (4) displays the voltage measured at that point (3).