L = Low Mode which provides 5Volts to the controller which will dim or raise the lighting of course depending on which mode you came from previously and will also of course raise or lower the fan speed.
S = Silent Mode which provides 0 Volts to the controller, turning off the fans and with it the light the LED provide.
H – High Mode which provides 12 volts to the controller raising the fan speed, increasing the lighting to the LED lights and with that increases the noise, but barely.
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