Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test I: Control Head Illumination/Display Does Not Operate Properly
2004 Oldsmobile Bravada AWDSECTION Test I: Control Head Illumination/Display Does Not Operate Properly
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
- Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing system check, go to next step.
- If DTC B2646 is displayed for Instrument Panel Module (IPM), see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. The IPM determines exterior light intensity based on voltage input from sun load sensor. If DTC B2646 is not displayed for Instrument Panel Module (IPM), go to next step.
- Connect scan tool. Turn ignition on, engine off. With scan tool, perform DISPLAYS TEST command in INSTRUMENT PANEL SPECIAL FUNCTIONS. If all HVAC control head segments illuminate, go to next step. If all HVAC control module segments do not illuminate, go to step 7.
- Perform DISPLAYS TEST command in INSTRUMENT PANEL MODULE SPECIAL FUNCTIONS. If all Vacuum Fluorescent (VF) displays illuminate, go to next step. If all VF displays do not illuminate, see appropriate ILLUMINATION/INTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT.
- Cover Sunload Sensor assembly. Turn on headlights. If control head backlighting does not illuminate, see appropriate ILLUMINATION/INTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT. If backlighting illuminates, go to next step.
- Adjust dimming control from minimum to maximum intensity. If VF display increases in intensity, system is okay. If VF display does not increase in intensity, go to next step.
- Check for loose wires and/or poor connections at HVAC Control Module. If any poor connections are found repair as necessary. When repair is complete, go to step 9. If poor connections are not found, go to next step.
- Replace HVAC Control Module. See HVAC CONTROL MODULE under REMOVAL & INSTALLATION. Go to next step.
- Operate system to verify repair. If condition is corrected, system is okay. If condition is not corrected, go to step 2.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.