ProLite Plus Owner's Manual page 151

HITCH AND INSTALLATION
The fail switch is powered by a 12-volt battery. If separation occurs, a shaft is pulled out of
the switch and the battery current from the recreational vehicle is applied to the trailer's
brakes.
Before hitching your trailer, you must read the instructions provided by the hitch
manufacturer. All Prolite trailers accept a two-inch-diameter ball. The following instructions
apply in most cases but if they differ from those provided by the hitch manufacturer, follow
the latter and disregard the information below:
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WARNING
Do not attach the emergency fail switch cable to any removable part of
the hitch.
WARNING
The fail cable must be secured to the towing vehicle, so it will remain
connected if the trailer hitch disconnects from the hitch ball.
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