GM Service Manual Online
For 1990-2009 cars only

Electrical troubleshooting requires the use of common electrical test equipment.

Test Light

A test light enables you to simply and quickly check a circuit for voltage.

The J 34142-B test light is made up of a 12 volt light bulb with an attached pair of leads.

  1. Gournding one lead
  2. Touch the other lead to various points along the circuit where voltage should be present.
  3. When the bulb illuminates, there is voltage at the point being tested

A J 21008-A self-powered test light allows you to check for continuity. This tool is made up of a light bulb, battery, and two leads. If the leads are touched together, the bulb illuminates. A self-powered test light is used only on an unpowered circuit.

  1. Remove the fuse which feed the circuit you're working on.
  2. Select two specific points along the circuit through which there should be continuity.
  3. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go on. Never use a self-powered test light on circuits that contain solid state components, since damage to these components may result.