GM Service Manual Online
For 1990-2009 cars only

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

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

Is the HUD display visible?

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

Go to Step 3

3

  1. Turn the ignition OFF.
  2. Disconnect the HUD module connector.
  3. Turn the ignition ON, with the engine OFF.
  4. Test for an open, for a short to ground, and a short to battery in the ignition circuit of the HUD module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 4

4

  1. Connect a test lamp between the dimmer signal circuit of the HUD and battery positive voltage. Refer to Circuit Testing in Wiring Systems.
  2. Turn the HUD dimmer switch to the off position.

Does the test lamp illuminate?

Go to Step 5

Go to Step 6

5

Disconnect the HUD dimmer switch.

Does the test lamp still illuminate?

Go to Step 8

Go to Step 7

6

Inspect for poor connections at the harness connector of the HUD module. 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

7

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

8

Repair a short to ground in the dimmer signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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9

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

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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