GM Service Manual Online
For 1990-2009 cars only

    Object Number: 1964003  Size: SH
  1. Have an assistant inside of the vehicle in order to locate the leak.
  2. Important: Use a water hose without the nozzle attached.

  3. Begin testing at the base of the window or the windshield.
  4. Slowly move the hose upward and across the top of the vehicle.