A Toyota Hilux recently rolled into the Romano’s Automotive workshop with a common but frustrating complaint: no power to the trailer plug. 🔍 With towing season in full swing across Perth, a dead trailer circuit isn’t just an inconvenience, it’s a legal and safety issue. Here’s how our team traced the fault, identified the culprit, and had this Hilux ready to hitch up again.
The Initial Diagnosis
When a trailer plug shows no signs of life, most people assume it’s a wiring issue at the plug itself. In reality, the fault often sits much further upstream. Our first step was to inspect the trailer circuit fuse. On removal, we noticed visible corrosion on the fuse block contacts, an early red flag.
To rule out a supply-side fault, we tested voltage directly at the supply wire feeding the fuse. Power was present, which confirmed the issue wasn’t upstream. The problem was localised to the fuse block itself: the contacts were passing voltage to the fuse, but corrosion was preventing a clean connection through it.
The Repair Process
Rather than simply swapping the fuse and hoping for the best (a common shortcut that leads to repeat failures), we carried out a proper repair:
- Removed the fuse block for full access to the contacts
- Cleaned the corroded terminals to restore conductivity
- Tightened the fuse pins to eliminate loose connections
- Cleared debris and moisture from inside the block
- Installed a new fuse and reassembled the unit
With everything back together, we tested voltage at the trailer plug across every circuit, including running lights, indicators, brake lights, and earth. All circuits tested serviceable and within spec.
Why Corrosion Happens
Perth’s coastal climate and the harsh conditions Hiluxes get put through, dust, moisture, off-road use, all contribute to fuse block corrosion over time. Trailer circuits are particularly vulnerable because they’re often used intermittently, allowing moisture to sit and oxidise the contacts. Regular inspection of towing-related fuses and connectors is a smart preventative habit, especially before long trips or heavy towing seasons.
Book Your Trailer Wiring Diagnostic in Perth
If your trailer lights are flickering, cutting out, or refusing to work altogether, don’t wait for a roadside pull-over to sort it. The team at Romano’s Automotive in Perth specialises in accurate auto electrical diagnostics, from fuse block faults to full trailer wiring rebuilds. Give us a call on 0401 747 320 or text 0482 074 129, or book online at https://shopcommand.com.au/book/romanos-automotive and we’ll have your rig ready to tow safely and legally.
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