Head Up Display (HUD) Always On

Head Up Display (HUD) Always On

Diagnostic Instructions

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

Diagnostic Fault Information






Circuit/System Description

The head-up display (HUD) is a secondary display system capable of reflecting important vehicle information onto the windshield. The vehicle information is displayed using virtual imaging and is reflected off the windshield in front of the driver. Battery positive voltage is the power source to the HUD system. The HUD system can only be enabled when the ignition is active and in RUN position. The HUD receives vehicle information to be displayed via the serial data circuit. The HUD system also receives vehicle speed information via discreet vehicle speed signal circuit. The HUD interfaces with the HUD switch via discreet circuits and the HUD switch inputs to the HUD is low. The dim select switch initiates a smooth increase in the HUD display 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 dim select switch. The dim select switch initiates a smooth decrease in the HUD intensity until the switch is released or the HUD is turned off.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the dimming/head-up display (HUD) switch.
2. Test for less than 1 ohm of resistance between the HUD switch ground circuit terminal 1 and ground.

• If greater than 1 ohm, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Dim Select Switch parameter is Inactive.

• If not Inactive, test the dimmer switch up signal circuit terminal 2 or the dimmer switch down signal circuit terminal 3 for a short to ground. If the circuit(s) tests normal, replace the HUD.

4. Install a 3A fused jumper wire between the dimmer switch up signal circuit terminal 2 or the dimmer switch down signal circuit terminal 2 and the ground circuit terminal 1. Verify the scan tool Dim Up Switch/Dim Down Switch parameter is Active.

• If any is not Active, test the appropriate dimmer switch signal circuit terminals 2 or 3 for a short to voltage or an open/high resistance. If the circuit(s) tests normal, replace the HUD.

5. If all circuits test normal, test or replace the HUD switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Programming and RelearningProgramming and Relearning
* Head Up Display Switch Replacement. Verification Tests