ParkAvenue 1997-1999



Specific to:

Buick LeSabre 1986-1999

Buick Park Avenue 1996-1999

Oldsmobile 88 1992-1999

Oldsmobile Delta 88 1986-1988

Oldsmobile LSS 1996-1999

Pontiac Bonneville 1987-1999

  1. Start the engine and pull out the defogger switch knob.
  3. Using a test lamp, ground the end and touch the probe to each grid line. The test lamp should operate as indicated.
  5. If the test lamp remains bright at both ends of the grid lines, check for a loose ground.

The range zones may vary slightly from one glass to another, but the test lamp brilliance will decrease proportionately as it is moved from left to right on the grid line.

  1. If an abnormal reading is observed by the test lamp on any grid line, place the test lamp probe on the left of that bus bar and move the probe toward the right until the test lamp goes out. This will indicate a break in the continuity on that grid line.

Click image to see an enlarged view

Fig. Use a test lamp to check the rear defogger for a broken grid