Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the HUD module.
- Connect a test lamp between the battery positive voltage circuit and the dimmer switch display signal circuit.
- Ignition ON, verify that a test lamp illuminates and changes intensity when the dimmer switch is adjusted from low to high intensity.
- If the test lamp does not vary in intensity, test the dimmer switch display signal circuit for an open/high resistance. If the circuit tests normal, replace the HUD switch.
- If all circuits test normal, test or replace the HUD module.