GM Service Manual Online
For 1990-2009 cars only

If the wipers miss or shudder when wiping the windshield and the windshield wipers and wiper inserts are clean, check the wiper arm pressure. If the wiper arms are not within specifications, replace the wiper arms. Refer to Windshield Wiper Arm Replacement . Complete the following steps in order to check the wiper arm pressure:

  1. Position the wiper arm in the center of the windshield.
  2. Attach a tension scale at the end of the wiper arm.
  3. While pulling on the scale, lift the wiper arm approximately 13 mm (0.5 in) above of the windshield.
  4. Measure the wiper arm pressure. Ensure that the wiper arm pressure is between 7.8-9.5 N (28-34 oz).

Blade Insert Set Check

Remove the wiper blade assemblies from the wiper arms. Look down the length of the blade insert. The rubber insert that contacts the glass must be on the center line of the blade or no more than 15 degrees. Replace the insert if necessary.