GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Tahoe - 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.

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

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.