A persistent electrical fault had not been resolved, with two important symptoms present: the battery charging warning lamp remained on, despite the charging system appearing to be working correctly, and the heater blower was broken. Previous repair attempts included three alternator replacements, a wiring repair and even a new Body Systems Interface module. None of these fixed the issue.
Solution
During these diagnosis assessments and repair attempts, this vehicle was part of a ‘transitional period’ for PSA Group electrical architecture. Peugeot and Citroën were moving from conventional wiring systems to multiplexed networks and CAN bus technology, resulting in variations in component locations and circuit design between seemingly identical models.
Initial investigation using the OEM wiring diagrams available through ALLDATA Repair showed an engine-running relay within the affected circuit; however, while the diagram confirmed its existence, its physical location was not clear. Working with the ALLDATA Info Centre, however, the workshop was able to access an archived manufacturer bulletin that identified the relay’s location – beneath the under-bonnet fuse box.
With this information, the technician quickly located the relay and performed bypass testing. This restored system operation and confirmed the fault path. Further testing showed the vehicle’s true wiring, narrowing the diagnosis to the alternator – despite multiple replacements. With access to genuine OEM data, though, the technician could fit a replacement alternator with confidence and knowledge that the faults would be resolved.
Without access to the original OEM wiring information and supporting manufacturer documentation, it is likely the workshop would have replaced more components, while the customer would have faced additional labour costs and uncertainty as to the fate of their vehicle. Instead, the root cause was found, allowing a vehicle that was considered for scrap to be put back on the road.
Why OEM information matters
Electrical faults on transitional vehicle platforms can be challenging. Production changes, evolving electrical architectures and differing component locations can make diagnosis difficult. This Inside Intelligence bulletin, however, demonstrates the value of combining OEM repair information with expert technical support.
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ALLDATA provides the latest, unedited technical information – directly from the manufacturer. This includes TSBs, recalls, and technical updates that are not always clearly identified in standard documentation. With data from 44 VMs and more than 167,000 unique combinations of make, model, year and powertrain – representing 97% of the European car parc – ALLDATA is a vital workshop companion.
