Head Up Display (HUD) Intensity Does Not Vary. Buick Park Avenue 2005

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2005 🢒 Park Avenue 🢒 Body 🢒 Instrument Panel, Gages, and Console 🢒 Head Up Display (HUD) Intensity Does Not Vary

Step	Action	Yes	No
Schematic Reference: Head Up Display Schematics
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Turn ON the ignition, with the engine OFF. Adjust the head up display (HUD) dimmer switch to full intensity then back to full dim. Does the HUD dim properly?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Is the HUD up/down switch also inoperative?	Go to Step 4	Go to Step 5
4	Turn OFF the ignition. Disconnect the HUD module connector. Turn ON the ignition, with the engine OFF. Connect a test lamp between the dimming signal circuit at the HUD module connector and a good ground. Adjust the HUD to full intensity then back to full dim. Does the test lamp go from full intensity then dim?	Go to Step 8	Go to Step 6
5	Turn OFF the ignition. Disconnect the HUD switch connector. Test the HUD switch ground circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 11	Go to Step 7
6	Test the dimming signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 11	Go to Step 7
7	Inspect for poor connections at the harness connector of the HUD switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 11	Go to Step 9
8	Inspect for poor connections at the harness connector of the HUD module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 11	Go to Step 10
9	Replace the HUD switch. Refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information. Did you complete the replacement?	Go to Step 11	--
10	Replace the HUD module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?	Go to Step 11	--
11	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2