2016 Honda Accord: Diagnosing and Repairing No Low Beams Caused by Wire Damage

Initial Diagnosis and Customer Complaint

• 💡 The customer reported no low beams on a 2016 Honda Accord, while high beams and other lights were functional.
• ⚠️ Previous attempts by the customer to replace the switch and by another shop to fix the issue were unsuccessful.
• 💰 The customer mentioned a quote of approximately $5,000 from Honda for the repair.

Electrical System Investigation

• 🔍 Initial checks confirmed no power to the low beam headlights with the switch in the 'on' position.
• ⚡ Applying direct power to the brown wire at the headlight connector successfully illuminated the low beam bulb, indicating the bulb and ground were likely good.
• 🗺️ Consulting a wiring diagram revealed the low beams are powered through fuse 24 and 25, and a headlight relay, drawing power from fuse 12-6.

Fuse Box and Relay Issues

• 📦 The under-hood fuse box showed significant damage, with relays missing, smashed, and terminals tampered with, suggesting poor previous repair work.
• 🔍 Testing the fuse box revealed no power on the expected terminals for the headlight relay, despite the headlights working when power was manually applied to the fuses.
• 🧩 A critical headlight relay was found to be missing from the fuse box.

Discovery of Damaged Wiring

• 🕵️‍♂️ A thorough visual inspection of the wiring harness near the fuse box revealed a broken light blue wire (control wire for the relay) that was difficult to spot due to its location and size.
• 🛠️ This broken wire was identified as the likely cause for the lack of control signal to the headlight relay.

Temporary Repair and Recommendations

• 💡 A temporary repair was performed by soldering and heat-shrinking an extension onto the broken blue wire and installing a new relay and pigtail assembly.
• ✅ With the temporary fix, the low beams, high beams, and fog lights were all confirmed to be working.
• ⚠️ The technician emphasized that this is a temporary repair and recommended a complete replacement of the wiring harness and fuse box for a proper, permanent fix.
• 📝 The customer will be required to sign a waiver acknowledging the temporary nature of the repair and advising against driving at night.