Hot Joints are a common problem to find in electrical connections on your trailers and inside your caravans. A hot joint is an electrical connection that becomes loose over time or connected by only a few strands in the connector ferrule.
This simple ECU has 5 pole or circuits and the main power circuit. It draws power from the battery and powers lights through relays in the ECU. Therefore the car computer does not know it is connected as there is no extra circuitry or resistance that can be detected by the vehicle computer.
This unit, the caravan and trailer electrics guide, discusses common electrical parts and components seen on modern road vehicles (such as sway controllers, ABS, to ECU).
The Couplemate™ Technical Hub is a free digital resource for the Australian towing and trailer industry. Units in the Technical Hub include: