As trailers become more complex, with telematics and diagnostics systems of their own, more auxiliary equipment and more sensitive electronics, the need to keep those systems running will become more challenging. We are already close to capacity in terms of circuits coming from the tractor, hamstrung by the limits of the traditional 7-pin trailer connector. But engineers are thinking beyond 7-pins to 15 pins, and even self-supporting trailer electrical systems that can power auxiliary systems onboard the tractor. That's a bit of a role reversal, and it may be closer than you think.
How often do drivers report an antilock braking system fault on the trailer, only to find in the shop that the center pin in the 7-way plug was not putting out any power? That pin is the only route to the trailer for power destined not only for the ABS, but also for automatic tire inflation systems, telematics, etc. At times there can be a lot of power traveling through that line, or not. If the fuse is blown, nothing on that circuit works. If the connector is badly corroded, voltages can be compromised, resulting in fault codes and poor component performance.
