Two-in-One Trailer Circuit Detector, compatible with 4-pin, 7-hole trailer interfaces, suitable for trucks and caravan trailers. After power-on, the indicator lights clearly show the status of each circuit line, enabling quick detection of open circuits and wiring errors. The body is shock-resistant and durable. It can be plugged in directly using the vehicle battery power supply. It is portable and compact, serving as a regular tool for trailer circuit maintenance.

The equipment is fully integrated with 4-channel and 7-channel dual-specification docking ports. Without the need to replace any accessories, it can be compatible with two mainstream connectors, and is applicable to the majority of freight trailers, travel trailers, and towing trailers. On the front of the body, there are multiple sets of status indicator lights. After connecting to the power supply of the vehicle, various vehicle lights will be turned on one by one, and the corresponding indicator lights will light up simultaneously. Maintenance personnel can directly determine whether each circuit is powered normally, accurately locate the fault points such as open circuits, loose connections, incorrect wiring, and reversed positive and negative poles, and the detection results are clear at a glance. It does not require complex professional knowledge to operate.This two-in-one trailer circuit detector is compatible with two common trailer interfaces: 4-pin and 7-hole. It is specifically designed for detecting the circuits of trucks, campers, trailers, and truck trailers. It can quickly identify faults in tail lights, brake lights, turn signals, and width indicator lines. It is an essential tool for auto repair shops, truck owners, and campervan enthusiasts for daily maintenance. It efficiently resolves various circuit problems such as abnormal trailer connections and faulty lights.
The casing is made of high-strength engineering plastic injection molding, with a thick and durable texture that is resistant to drops and wear. It is unlikely to crack or damage even when bumped in the workshop or used in outdoor rain and snow environments. The internal metal conductive contacts are treated with thick electroplating, ensuring smooth conductivity and preventing oxidation and rust. After tens of thousands of plug-ins and unplugs, the contact remains stable, and there will be no situation of poor contact and incorrect detection results. The overall design is compact and portable, requiring no external power supply. It can conduct detection using the vehicle's 12V onboard battery in a cramped space for maintenance.
Previously, troubleshooting trailer lighting faults required disassembling and measuring each circuit line one by one, which was time-consuming and cumbersome. Using this tester, the connection ports can be plugged in to verify all vehicle lighting circuits in one click, significantly reducing the maintenance time and improving the repair efficiency. It can be used for new vehicle wiring calibration, old trailer wiring repair, and trailer wiring bundle verification, effectively avoiding the risks of being fined by traffic control due to lighting faults on the road or rear-end accidents caused by tail lights failure during driving.
The entire device does not require calibration and can be plugged in and used directly. It does not occupy space and is convenient to carry with the vehicle. It is made with solid and durable construction, catering to both commercial and personal use needs in auto repair. It is a practical and convenient professional tool for trailer circuit maintenance.