GM Service Manual Online
For 1990-2009 cars only

Various Heads Up Display (HUD) Conditions - keywords appearance display IPC windshield

Subject: A customer may comment on any of the following conditions related to HUD

Models:1999-2005 Buick Park Avenue
2005-2009 Cadillac STS
2004-2009 Cadillac XLR
1999-2009 Chevrolet Corvette
2006-2009 GMC Acadia
1999-2005 Pontiac Bonneville, Grand Prix



This PI was superseded to update models. Please discard PIC3379A.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

  1. The HUD image may not appear clear. If inspected closely, there appears to be two similar images, often described as a "ghost image". This concern may be noticeable especially during low ambient light conditions - early morning or in the evening - or when a dark object is present in front of the vehicle in the viewing area of the HUD.
  2. Condition: All segments of the HUD illuminate intermittently.
  3. Condition: Poor/hazy HUD image.

Recommendation/Instructions:

  1. The HUD image is projected on the surface of the windshield glass. Since a windshield is composed of two thicknesses of glass, there are two reflections. In order to align these two images, a wedged shaped plastic laminate is used between the two layers of glass. If the dimensions of the plastic laminate are not correct, the images will not fully align and the HUD image will not appear clear. In order to diagnose this condition, you can apply Vaseline to the outside of the windshield in the area of the HUD display. If there is no longer a "ghost" image, the problem can be attributed to the windshield. The extent of the "ghosting" can be helpful in determining if the vehicle has the proper windshield. If the "ghosting" offset is greater than 25% of the width of a line/bar of a HUD character, the vehicle likely does not have a HUD windshield. If the offset is less, or the vehicle definitely has a HUD windshield, another windshield can be installed that may have less distortion/variance. Use of a non-OEM HUD windshield may result in this condition. Use of a non-HUD windshield will result in this condition. HUD windshields should be identified in the lower right corner of the windshield.
  2. Under certain ambient lighting conditions, it could appear that all of the various segments within the HUD are on. Typically, further questioning of the customer will reveal a correlation between the time of day and what direction the vehicle is traveling in relation to the sun. This is a normal condition if the sun is shining at a certain angle directly into the HUD display.
  3. New IP pads may emit fumes that cause a film to form on the HUD lens. Regular household cleaners will not remove this type of film. Rubbing alcohol should be used to clean the lens.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.