GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Corvette 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC B3634

Circuit Description

The head-up display (HUD) monitors the HUD dimming up switch signal circuit in order to perform the switch functions. When the HUD dimming up switch is depressed and the ignition is in the RUN position, the dimming switch signal to the HUD is low. When the HUD detects that the HUD dimming switch signal is low for greater than 60 seconds, DTC B3634 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3634 Head Up Display (HUD) Dimming (Up) Switch Circuit

Conditions for Running the DTC

The ignition is RUN.

Conditions for Setting the DTC

The HUD detects that the HUD dimming up switch signal circuit is low for greater than 60 seconds.

Action Taken When the DTC Sets

The HUD ignores the malfunctioning switch circuit.

Conditions for Clearing the DTC
    • The current DTC clears when fault is no longer present but all history codes remain.
    • The HUD receives a clear code command from the scan tool.

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

2
  1. Turn On the ignition, with the engine ON.
  2. Adjust the HUD dim up switch to maximum intensity and then to minimum intensity.

Does the HUD dim up switch operate correctly?

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.
  3. With the dim up switch adjusted to the least minimum intensity, connect a test lamp between the HUD dimming up switch signal circuit and battery positive voltage. Refer to Circuit Testing in Wiring Systems.
  4. Turn ON the ignition, with the engine ON.

Does the test lamp illuminate?

Go to Step 4

Go to Step 6

4

Test the HUD dimming up switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at 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 9

Go to Step 7

6

Inspect for poor connections at 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 9

Go to Step 8

7

Replace the HUD switch. Refer to Switch Replacement - Ignition and Start, DIC Display and HUD Dimmer .

Did you complete the replacement?

Go to Step 9

--

8

Replace the HUD. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

9
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

System OK

Go to Step 2