GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC C Pickup - 2WD 🢒 Body and Accessories 🢒 Air/Wind Noise 🢒 Soap Suds or Bubble Test
  1. Mask off the pressure relief valves.
  2. Turn ON the vehicle's ventilation fan.
  3. Close all the windows and the doors.
  4. Apply the soap solution to the potential leak areas.
  5. Look for bubbles revealing escaping air.