GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Corvette 🢒 Body 🢒 Instrument Panel, Gages, and Console 🢒 DTC B3744

Circuit Description

The head-up display (HUD) monitors the HUD mode switch signal circuit in order to perform the switch functions. When the HUD mode switch is depressed and the ignition is in the RUN position, the mode switch signal to the HUD is low. When the HUD detects that the HUD mode switch signal is low for greater than 60 seconds, DTC B3744 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3744 Head Up Display (HUD) Mode Switch Circuit

Conditions for Running the DTC

The ignition is RUN.

Conditions for Setting the DTC

The HUD detects that the HUD mode 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. Press and release the HUD mode switch to change the modes displayed in the HUD.

Does the HUD mode 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 mode switch released, connect a test lamp between the HUD data 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 data 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