The LED CHMSL setting covers both the stop lamp and cargo lamps circuits for when the cargo cam CHMSL is used. Normally, all exterior lighting uses PWM when halogens are used. The LED light settings shuts off the PWM on the circuit so LEDs can be used without flickering or throwing errors. This setting in particular is also important if LEDs are going to be used in the upper brake light. If the LEDs installed in that spot have poor quality filtering circuits built in, along with the PWM, they could potentially cause EMI with the RF Hub mounted close by. Since the brake needs to be pressed for the rf hub to send the start command, it’s possible that cheap LEDs could interfere with the RF Hub and cause something like a “key fob not detected”. Shutting off the PWM to that brake lamp circuit will nearly eliminate that phenomenon.