Left fan is wired to turn on and off automatically from the factory fan temperature sensor. The right fan gets power from the battery and you turn it on and off from a handlebar power switch.

2004-2014 TRX450R & ER. Big Fan Kit with Full Shroud. Fan wired to run all of the time version.

TRX450R/ER Big Fan Kit with Full Shroud. Wired to turn on and off automatically from the factory fan temperature sensor.

Big Fan Kit 2004-2014 TRX450R & ER. Big Fan Kit with Small Shroud. Fan wired to run all of the time version. (Small shroud dessert, MX and TT.)