GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Head Up Display Schematics

1

Did you perform the HUD Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Head Up Display

2

  1. Turn the ignition ON, with the engine OFF.
  2. Adjust the head up display (HUD) dimmer switch from the lowest intensity to the highest intensity.

Does the HUD dim properly?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Move the HUD image up and down.

Does the image move up and down?

Go to Step 4

Go to Step 6

4

  1. Turn the ignition OFF.
  2. Disconnect the HUD module.
  3. Turn the ignition ON, with the engine OFF.
  4. Connect a test lamp between the HUD dimmer signal circuit and battery positive voltage.
  5. Adjust the HUD from the lowest intensity to the highest intensity.

Does the test lamp go from full intensity then to full dim?

Go to Step 7

Go to Step 5

5

Test the HUD dimmer signal circuit for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

6

Test the HUD dimming switch ground circuit for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

7

Inspect for poor connections at the harness connector of the HUD. Refer to Testing for Intermittent Conditions and Poor Connections and to 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 dimmer switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the HUD module. Refer to Head Up Display Module Replacement .

Did you complete the replacement?

Go to Step 11

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10

Replace the HUD dimmer switch. Refer to Head Up Display Switch Replacement .

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2