Electrical problems are becoming increasingly common in VT and VX Commodores as these vehicles age. While Holden significantly improved vehicle electronics compared to earlier Commodore generations, ageing wiring, failing modules, worn switches, and deteriorating connectors can cause a wide range of frustrating faults.
Electrical issues can range from simple blown fuses to complex Body Control Module (BCM) failures that affect multiple vehicle systems. Understanding the most common problems can help owners diagnose faults quickly and avoid unnecessary parts replacement.
Why Electrical Problems Occur
Most electrical faults are age-related.
Common Causes
- Corroded connectors
- Poor earth connections
- Worn switches
- BCM faults
- Alternator problems
- Wiring deterioration
- Moisture intrusion
Many VT and VX Commodores are now over 20 years old, making electrical wear increasingly common.
Common Electrical Symptoms
Warning Signs
- Intermittent starting problems
- Flat batteries
- Interior electrical failures
- Warning lights
- Central locking issues
- Lighting faults
- Random electrical behaviour
Electrical faults often appear intermittently before becoming permanent.
1. BCM (Body Control Module) Problems
The BCM controls many vehicle functions.
Symptoms
- Central locking faults
- Interior light issues
- Security system problems
- Battery drain
- Electrical glitches
Causes
- Internal BCM failure
- Water damage
- Connector corrosion
The BCM is one of the most common electrical fault sources in VT and VX Commodores.
Typical Repair
- Check wiring and connectors
- Replace or repair BCM if necessary
2. Battery Drain Problems
A common complaint among owners.
Symptoms
- Flat battery overnight
- Battery repeatedly discharged
- Slow cranking
Causes
- BCM staying awake
- Faulty accessories
- Wiring faults
- Interior light issues
Parasitic current draw testing is usually required.
3. Alternator Failure
Alternators commonly wear with age.
Symptoms
- Battery warning light
- Dim headlights
- Low charging voltage
- Flat battery
Causes
- Worn brushes
- Regulator failure
- Internal alternator wear
Typical Repair
Replace or rebuild the alternator.
4. Poor Earth Connections
One of the most overlooked electrical faults.
Symptoms
- Intermittent faults
- Starting issues
- Lighting problems
- Instrument cluster glitches
Causes
- Corroded earth points
- Loose ground straps
Poor earths can mimic major component failures.
5. Power Window Problems
Common on ageing VT and VX models.
Symptoms
- Windows stop working
- Slow window movement
- Intermittent operation
Causes
- Window regulator failure
- Switch wear
- Wiring issues
Typical Repair
Inspect switches before replacing regulators.
6. Central Locking Failures
A frequent complaint.
Symptoms
- Doors won’t lock
- Doors won’t unlock
- Remote entry problems
Causes
- BCM faults
- Door actuator failure
- Wiring problems
7. Instrument Cluster Issues
Clusters can develop faults over time.
Symptoms
- Gauges not working
- Flickering displays
- Incorrect readings
Causes
- Internal circuit faults
- Connector issues
- Voltage supply problems
8. Headlight and Lighting Problems
Lighting faults are common on older Commodores.
Symptoms
- Dim headlights
- Intermittent lights
- Non-functioning bulbs
Causes
- Corroded connectors
- Faulty switches
- Wiring deterioration
9. Ignition Switch Problems
The ignition switch handles significant electrical load.
Symptoms
- Intermittent starting
- Accessories not functioning
- Electrical dropouts
Causes
- Internal switch wear
Typical Repair
Replace ignition switch assembly.
10. Security System Faults
Security-related issues often involve the BCM.
Symptoms
- Immobiliser activation
- No-start conditions
- Security warning lights
Causes
- BCM faults
- Key recognition issues
- Wiring problems
Typical Repair
Diagnose BCM and security system communication.
11. Blower Fan Problems
A common comfort-related issue.
Symptoms
- Fan only works on some speeds
- No blower operation
Causes
- Resistor failure
- Blower motor wear
- Wiring issues
12. Fuel Pump Electrical Faults
Electrical faults can prevent fuel delivery.
Symptoms
- Crank but no start
- Intermittent stalling
Causes
- Fuel pump relay
- Wiring faults
- Pump connector issues
How to Diagnose Electrical Problems
Step 1: Check Battery Condition
A weak battery can create multiple symptoms.
Check
- Battery voltage
- Terminal condition
- Charging system performance
Step 2: Check Fuses
Inspect:
- Engine bay fuse box
- Interior fuse panel
Always test rather than visually inspect where possible.
Step 3: Check Earth Connections
Verify all major ground points.
Step 4: Scan for Fault Codes
Many electrical faults trigger diagnostic trouble codes.
Step 5: Inspect Connectors
Look for:
- Corrosion
- Moisture
- Loose terminals
Most Common VT, VX Electrical Problems Ranked
1. BCM Faults
Most common major electrical issue.
2. Alternator Failure
Very common with age.
3. Battery Drain
Frequently reported by owners.
4. Power Window Problems
Common wear-related fault.
5. Earth Connection Issues
Often misdiagnosed.
Common Electrical Fault Misdiagnoses
Blaming the BCM Too Quickly
Many faults originate elsewhere.
Replacing the Battery Unnecessarily
Battery problems are often symptoms rather than causes.
Ignoring Earth Connections
Ground faults cause numerous electrical issues.
Replacing Components Without Testing
Proper diagnosis saves money.
Preventing Electrical Problems
Maintain Battery Health
Protects electronic systems.
Keep Connectors Dry
Moisture accelerates corrosion.
Repair Small Faults Early
Prevents secondary issues.
Inspect Earth Points Regularly
Improves overall reliability.
Warning Signs Requiring Immediate Attention
- Repeated battery drain
- No-start conditions
- Burning electrical smells
- Security system faults
- Charging system failure
Prompt diagnosis is recommended.
Electrical problems in VT and VX Commodores are becoming increasingly common as these vehicles continue to age. BCM faults, alternator failures, battery drain issues, poor earth connections, and ageing wiring are among the most frequent causes of electrical trouble.
Fortunately, many of these problems can be diagnosed with a systematic approach and repaired without excessive expense. Regular inspections, healthy charging systems, and attention to wiring and connectors can significantly improve reliability and help keep these iconic Commodores on the road for years to come.
Related Articles
- VT, VX BCM Fault Guide
- VT, VX Commodore Suspension Problems
- VT, VX Power Steering Problems
- Common Ecotec Engine Problems
- Best Scan Tools for Holden Owners
- How to Inspect a VT or VX Commodore Before Buying