Forum Discussion
msturtz
Apr 12, 2017Explorer
A couple of notes you should be aware of. The transmission should be in Park not Drive per the manual. Next, if you are using a braking system that ties into the vehicle battery or in certain situations the vehicle can actually become reenergized in a round about way. When you disconnect the battery negative cable that isolates the ground from the vehicle battery however in many installations there is still a ground connection to the battery from the tow vehicle electrical connection to allow the lights and braking system to work. The braking system needs power and generally there is a charge line to the toad vehicle in addition to the ground. The other way the toad vehicle computer can receive power is through the motorhome electrical system. In general there is +12V power available at the following pins: Battery charge line, reverse light, brake power, running lights and brake lights / turn signals. Since the motorhome has a common ground and the tow bar is in fact also a ground this allows current leakage through the hot side that is connected to the vehicle battery combined with the ground through the motorhome back feeding through any OEM component that is screwed or bolted to the frame. The solution is simple disconnect the "hot" side rather than the negative side.
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