Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC B3634: Head-Up Display (HUD) Dimming Up Switch Short to Ground.Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
HUD Switch Signal Circuit | B3619 | -- | -- | -- |
HUD Image Up Control Circuit | B3620 | -- | -- | -- |
HUD Image Down Control Circuit | B3621 | -- | -- | -- |
Illuminated Display Signal Circuit | B3634 | -- | -- | -- |
Circuit/System Description
The head-up display (HUD) dimming switch is a momentary press switch that adjusts the HUD display brightness. The HUD dimming switch controls the intensity of the brightness.The HUD switch dimming input is puledl up to 5 volts in the HUD. The HUD dimming switch is pulled down to ground via a 10K potentiometer. When the HUD dimming switch is pressed and the ignition is in the RUN position, the dimming switch signal to the HUD is low. The HUD senses when the dimming switch is active and adjusts the display brightness until the desired intensity is attained.
Conditions for Running the DTC
The ignition is in RUN.
Conditions for Setting the DTC
The HUD detects that the HUD dimming up switch signal circuit is low for greater than 60 seconds.
Action Taken When the DTC Sets
The HUD ignores the malfunctioning switch circuit.
Conditions for Clearing the DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction-free warm-up cycles. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Head Up Display (HUD) Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the head-up display (HUD) switch.
- Test for less than 1.0 ohm of resistance between the low reference circuit terminal 3 and ground.
- Ignition ON, test for 4.8 - 5.2 volts between the illuminated display signal circuit terminal 6 and ground.
- If all circuits test normal, test or replace the HUD switch.
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HUD. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for the HUD replacement, setup and programming |
