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The AU Falcon has a reputation that precedes it, and not always kindly. But beneath the styling debate and market reception sits an electrical system that represents a genuine transition point for Ford Australia — one foot still planted in the analogue world, the other stepping cautiously into electronic engine management.
System Overview
The AU Falcon runs a 12-volt negative earth electrical system built around largely conventional wiring, with early electronic engine management introduced through the PCM.
Key components include:
- Conventional alternator with internal regulator
- Maintenance-free lead-acid battery (factory specification)
- PCM-based engine management system
- Limited electronic integration between engine and transmission control
- Traditional fuse and relay distribution system
- Mechanical throttle control (cable-operated in most variants)
- Minimal body control module integration compared to later models
Unlike BA and later Falcons, the AU is still heavily “hard-wired.” Most systems operate independently rather than through shared digital networks.
Alternator and Charging System
The AU Falcon uses a conventional internally regulated alternator. It is not PCM-controlled in the modern sense, but it does operate under load-aware conditions depending on variant and year.
Typical specifications:
- Output range: ~85–110A depending on engine and specification
- Internal voltage regulator
- Belt-driven conventional design
- Fixed charging curve with minimal electronic modulation
Common part numbers:
- Ford OEM AU alternator assemblies (I6 and V8 variants)
- Bosch replacement alternators (very common aftermarket fitment)
- Denso and Mitsuba remanufactured units
Known issues:
- Voltage regulator failure leading to over/under charging
- Bearing wear due to heat and age
- Reduced output at idle under electrical load
- Diode pack failure causing battery drain
Compared to BA and later Falcons, AU alternators are simple — but also less efficient under modern accessory loads.
Battery System
The AU Falcon uses a conventional maintenance-free lead-acid battery from factory, with modest reserve capacity by modern standards.
Typical specifications:
- 12V maintenance-free lead-acid battery
- Moderate cold-cranking capacity
- Designed for basic electrical loads and daily driving
Common part numbers:
- Ford OEM AU battery group sizes (varies by engine)
- Century MF lead-acid batteries
- Exide maintenance-free replacements
- Bosch S3/S4 equivalents
Known issues:
- Rapid discharge with aged alternator systems
- Sulphation from short-trip driving
- Poor tolerance of aftermarket electrical loads
- Voltage drop leading to hard starting or dim lighting
Battery health is critical in AU Falcons — but the system is more forgiving than later electronic-heavy models.
Wiring and Control Systems
The AU Falcon is primarily a traditional wired electrical system with limited electronic integration.
Key systems include:
- PCM (Powertrain Control Module)
- Basic ABS module (where fitted)
- Mechanical transmission control (most variants)
- Simple instrument cluster with minimal digital integration
- Discrete wiring for lighting, accessories, and controls
Unlike BA and later Falcons, there is no full body control module managing all accessories. Instead, systems operate independently.
Benefits:
- Simple diagnostic process
- High tolerance for electrical faults
- Easy modification and repair
- Minimal dependency on module communication
Limitations:
- Wiring complexity compared to earlier EL
- Inconsistent refinement across systems
- Lack of integration between vehicle systems
- More manual relay and switch-based operation
Lighting and Accessories
The AU retains a largely traditional approach to lighting and accessories.
Features include:
- Manual headlight switching (most variants)
- Central locking (varies by trim)
- Electric windows and mirrors (higher trims)
- Basic interior lighting circuits
- Limited automation or delay functions
Common issues:
- Headlight switch wear and overheating
- Window regulator failure (mechanical and electrical wear)
- Earth point corrosion causing flickering lights
- Relay fatigue in lighting circuits
Electrical gremlins are common, but typically straightforward to diagnose.
Infotainment and Interior Electronics
Infotainment in the AU Falcon is relatively simple compared to later generations.
Features include:
- Single or multi-disc CD head units (depending on trim)
- Basic AM/FM radio integration
- Optional premium sound systems (higher trims)
- Minimal steering wheel control integration
Known issues:
- Head unit failure or display degradation
- Speaker wear and distortion over time
- Wiring fatigue in door looms
- Limited compatibility with modern aftermarket systems without adapters
Because of its simplicity, AU Falcons are popular for aftermarket stereo upgrades.
Electrical Weak Points
The AU Falcon has several well-known electrical weak points, many of which stem from age rather than design alone.
1. Alternator Reliability
Regulator and diode failures are common.
2. Earth Points
Corrosion leads to intermittent and confusing electrical faults.
3. Wiring Harness Ageing
Door looms and engine bay wiring can crack or fatigue.
4. Switchgear Wear
Headlight and window switches are known wear points.
Upgrade Potential
Despite its reputation, the AU Falcon is actually very modification-friendly electrically due to its simplicity.
Common upgrades include:
- High-output alternators for audio or lighting upgrades
- AGM battery conversions for improved reliability
- Upgraded grounding kits
- Modern head unit installations (double DIN conversions common)
- LED lighting upgrades (with relay considerations)
Because there is no heavy CAN-bus dependency, modifications are generally straightforward and reversible.
The AU Falcon electrical system sits at the uncomfortable intersection of old and new. It’s not as refined as the BA, nor as simple as earlier Falcons — but it represents an important evolutionary step in Ford Australia’s engineering direction.
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