GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Avalanche - 2WD 🢒 Power and Signal Distribution 🢒 Wiring Systems and Power Management 🢒 Measuring Voltage

Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

   • Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors
   • Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors
      -  Visually and functionally inspect the gloves before use.
      -  Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.
Failure to follow the procedure exactly as written may result in serious injury or death.

Notice: Do not insert test equipment probes (DVOM etc.) into any connector or fuse block terminal. The diameter of the test probes will deform most terminals. A deformed terminal will cause a poor connection, which will result in a system failure. Always use the J-35616 GM-Approved Terminal Test Kit in order to front probe terminals. Do not use paper clips or other substitutes to probe terminals.

When using the J-35616 GM-Approved Terminal Test Kit, ensure the terminal test adapter choice is the correct size for the connector terminal. Do not visually choose the terminal test adapter because some connector terminal cavities may appear larger than the actual terminal in the cavity. Using a larger terminal test adapter will damage the terminal. Refer to the J-35616 GM-Approved Terminal Test Kit label on the inside of the J-35616 GM-Approved Terminal Test Kit for the correct adapter along with the connector end view for terminal size.

The following procedure measures the voltage at a selected point in a circuit.

  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 ON the ignition, with the engine OFF.
    • Turn ON the engine.
    • Turn ON the circuit and/or system with a scan tool in Output Controls.
    • Turn ON the switch for the circuit and/or system being tested.
  3. Select the V (AC) or V (DC) position on the DMM.
  4. Connect the negative lead of the DMM to a good ground.
  5. Connect the positive lead of the DMM to the point of the circuit to be tested.
  6. The DMM displays the voltage measured at that point.