The head-up display (HUD) dimming up or dimming down switch is a momentary press switch that adjusts the HUD display brightness. The HUD dimmer up or dimmer down switch controls the intensity of the brightness. The HUD senses when the dimming up or dimming down switch is active and adjusts the display brightness until the desired intensity is attained. When the HUD dimming up switch is pressed and the ignition is in the RUN position, the dimming up switch signal to the HUD is low. A press and hold of the dimming up switch greater than 1 sec initiates a smooth increase in the HUD intensity until the switch is released or maximum intensity is achieved. The HUD does not have a separate Off switch. The HUD is turned OFF using the dimming down switch. When the HUD dimming down switch is pressed and the ignition is in the RUN position, the dimming down switch signal to the HUD is low. A press and hold of the dimming down switch greater than 1 sec initiates a smooth decrease in the HUD intensity until the switch is released or the HUD is turned OFF.

Schematic Reference

Head Up Display Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

1. Ignition OFF, disconnect the harness connector at the HUD.
2. Connect a test light between the HUD dimming up switch signal circuit terminal 11 or dimming down switch signal circuit terminal 12 and B+. Verify a test light goes from full intensity to dim or dim to full intensity while adjusting the HUD dimmer up or dimmer down switch.

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If the test light does not go from full intensity to dim or dim to full intensity, test the HUD dimming up switch signal circuit terminal 11 or dimming down switch signal circuit terminal 12 and the ground circuit terminal 6 for an open/high resistance. If the circuits test normal, replace the HUD switch.

3. If all circuits test normal, test or replace the HUD.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.