Easy Ford Battery Light Fix!

Table of Contents

• Introduction to the Issue
• Testing the Alternator
• Identifying the Problem Area
• Locating the Open Circuit
• Common Places to Look for the Open Circuit
• Running a New Wire
• Properly Securing the Wire
• Fixing the Problem
• Overview of the Repair Process
• Verifying the Solution
• Conclusion

Article

Introduction to the Issue

When working on a 2016 Ford F550 with a 6.7 Powerstroke diesel engine, there was a recurring problem of a battery light illuminating even though the alternator was still charging at times. While the initial suspicion was on a faulty alternator, further investigation revealed a common issue that required a closer examination of the wiring system.

Testing the Alternator

To identify the root cause of the problem, various tests were conducted. Initially, the alternator was tested, and it passed without any issues. It became evident that the problem lay elsewhere in the vehicle's electrical system.

Identifying the Problem Area

Upon reviewing the wiring diagram, it was observed that the powertrain control module (PCM) and its connectors played a crucial role in the charging system's operation. Attention was directed towards testing the voltage and continuity of the wires connecting the PCM to the alternator.

Locating the Open Circuit

Using a digital multimeter, tests were carried out on the wires leading to the PCM. The purple wire (terminal number 14) displayed good continuity, indicating no issues. However, the yellow wire (terminal number 53) exhibited no continuity at all, indicating the presence of an open circuit.

Common Places to Look for the Open Circuit

In search of the open circuit, common areas were inspected, but no visible signs of corrosion or damage were found. The wire harness was traced, but it disappeared under the engine, making it challenging to pinpoint the exact location of the corroded wire.

Running a New Wire

To rectify the problem and get the vehicle back on the road, a decision was made to run a new wire from the PCM to the alternator. By doing so, the faulty wire would be bypassed, ensuring that the battery light issue was resolved. It was crucial to ensure proper insulation and secure attachment of the new wire to prevent any future complications.

Properly Securing the Wire

When running the new wire, utmost care was taken to secure it properly and prevent any potential damage. Heat shrink was used to seal the spliced areas, and the wire was routed away from moving parts such as the cooling fan.

Fixing the Problem

After successfully replacing the problematic wire, the vehicle was started to test whether the battery light was still present. Fortunately, the battery light was no longer illuminated, indicating that the problem had been resolved. The codes were scanned, and the generator control circuit code (P0620) did not reappear, confirming the effectiveness of the repair.

Overview of the Repair Process

To provide an overview of the repair process, the steps taken were briefly explained. This included splicing the wire and using wiring loom and zip ties for proper protection and routing. The new wire was connected to the PCM and the alternator, ensuring a stable connection.

Verifying the Solution

To further confirm the success of the repair, voltage levels were checked using the vehicle's data display. A voltage of 13.2 to 13.3 volts indicated that the alternator was now charging correctly, providing assurance that the issue had been fully resolved.

Conclusion

In conclusion, the battery light issue in the 2016 Ford F550 was resolved by identifying and repairing an open circuit between the PCM and the alternator. By running a new wire and ensuring its proper installation, the problem was fixed without the need for an expensive replacement of the entire wiring harness or the alternator. This cost-effective solution provided by an experienced technician saved time and money while getting the truck back on the road efficiently.