GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Instrument Cluster Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

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

Is the HUD display visible?

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the HUD module.
  3. Turn the ignition ON, with the engine OFF.
  4. Test the ignition positive voltage circuit for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Repairs.

Did you find and correct the condition?

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Go to Step 11

Go to Step 4

4

Measure the voltage from the dimming signal circuit to a good ground.

Does the voltage measure near the specified value?

12 V

Go to Step 8

Go to Step 5

5

Test the dimming signal circuit for an open, short to ground, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Repairs.

Did you find and correct the condition?

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Go to Step 11

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Disconnect the HUD dimmer switch.
  3. Turn the ignition ON, with the engine OFF.
  4. Test the ignition positive voltage circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Repairs.

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 dimmer 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 dimmer switch. Refer to Head Up Display Module Replacement .

Did you complete the replacement?

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Go to Step 11

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10

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

Did you complete the replacement?

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Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2