Fog/Driving Lamp: Adjustments
STANDARD PROCEDURE - FRONT LAMP ALIGNMENT
VEHICLE PREPARATION FOR LAMP ALIGNMENT
1. Check for and correct any burnt out bulbs.
2. Repair or replace any ineffective, worn or damaged body or suspension components that could hinder proper lamp alignment.
3. Verify proper tire inflation pressures.
4. Remove any accumulations of mud, snow or ice from the vehicle underbody and clean the front lamp lenses.
5. Verify that there is no load in the vehicle (cargo or passengers), except for the driver.
6. The fuel tank should be FULL. Add 2.94 kilograms (6.5 pounds) of weight over the fuel tank for each estimated gallon of missing fuel.
7. Verify correct vehicle suspension height.
LAMP ALIGNMENT SCREEN PREPARATION
The procedure that follows will prepare a suitable front lamp alignment screen.
1. Tape a line on a level floor at the appropriate distance away from and parallel to the flat wall that will be used as the lamp alignment screen. Refer to the Lamp Alignment Screen Distance table for the appropriate measurement. The level floor will be used as the horizontal zero reference.
2. An adjacent wall or floor member that is perpendicular to the alignment screen can be used as the vertical zero reference. If there is no adjacent wall or floor member that is perpendicular to the screen, tape a second line on the floor perpendicular to both the alignment screen and the first line, and outboard of either side of where the vehicle will be positioned. This will be used as the vertical zero reference.
3. Position the vehicle so that the side of the vehicle is parallel to the vertical zero reference, and so that the front of the lamp lenses are in the vertical plane of the parallel line taped on the floor in Step 1.
4. Rock the vehicle side-to-side three times to allow the suspension to stabilize.
5. Jounce the front suspension three times by pushing downward on the front bumper and releasing.
6. Measure the distance between the optical center of one of the lamps being aimed (head or fog) and the floor (horizontal zero reference). Transfer this measurement to the alignment screen with a piece of tape placed horizontally to the floor. This line will be used as the lamp horizontal reference.
7. Measure the distance between the vertical zero reference and the optical center of the nearest lamp being aimed (head or fog). Transfer this measurement to the alignment screen with a piece of tape placed vertically across the appropriate (head or fog) lamp horizontal reference. This is the centerline reference for the first lamp.
8. Measure the distance on center between the first and the second lamp being aimed. Transfer this measurement to the alignment screen with a second piece of tape placed vertically across the appropriate (head or fog) lamp horizontal reference. This is the centerline reference for the second lamp.
HEADLAMP ALIGNMENT
NOTE: Vehicles equipped with the optional High Intensity Discharge (HID) headlamps include an automatic headlamp leveling feature, which uses axle sensor inputs to the Automatic Headlamp Leveling Module (AHLM) to automatically adjust the headlamp level to compensate for changes in vehicle cargo or passenger load. This feature must be disabled in order to successfully perform a manual headlamp alignment. Follow the steps outlined in the diagnostic scan tool under the AHLM Electronic Control Unit (ECU) Actuator menu item for HEADLIGHT LEVELING POSITION. The Actuator must be set to the DELIVERY POSITION during manual headlamp alignment, then remain in DELIVERY POSITION once adjustment is completed.
Figure 2 - Halogen Headlamp
Figure 3 - High Intensity Discharge (HID) Headlamp
NOTE: Due to the linear nature of the headlamp cutoff, a properly aimed low beam headlamp will project the top edge of the high intensity pattern on the alignment screen from the horizontal line to 50 millimeters (2 inches) below the horizontal line. No horizontal (right/left) adjustment is required for this headlamp beam pattern. The high beam pattern will be correct when the low beams are properly aimed.
1. Turn the headlamps ON and select the LOW beams.
2. Use a screwdriver to access the vertical adjustment screw (2) on the back of each front lamp unit housing (1). The adjustment screw is accessed through an oblong clearance hole provided in the right or left fender close out panel just behind each hood bumper. Rotate the headlamp vertical adjustment screw to adjust the beam height as required.
FOG LAMP ALIGNMENT
NOTE: A properly aimed front fog lamp will project a pattern on the alignment screen 100 millimeters (4 inches) below the fog lamp centerline and straight ahead of the lamp.
1. Turn the fog lamps ON.
2. Reach through the outboard opening in the front of the front wheel house splash shield to access the back of the front fog lamp.
3. Rotate the vertical adjustment screw (1) on each lamp to adjust the beam height as required.