Head Up Display (HUD) Intensity Does Not Vary

Head Up Display (HUD) Intensity Does Not Vary

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



Diagnostic Fault Information






Circuit/System Description

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 second 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 second initiates a smooth decrease in the HUD intensity until the switch is released or the HUD is turned OFF.


Reference Information
Schematic Reference

Head Up Display Schematics (Head Up Display Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Head Up Display (HUD) Description and Operation (Head Up Display (HUD) Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)


Circuit/System Testing

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.

• If the test light does not go from full intensity to dim or dim to full intensity, test the suspect signal circuit 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.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Control Module References (Programming and Relearning) for the HUD replacement, setup and programming
* Head Up Display Switch Replacement (Head Up Display Switch Replacement)