MoTeC Snowmobile Plug-In ECU - Manual (Page 14)

6 Yamaha Apex Installation MoTeC
Thumb Warmer and Grip Warmers
The standard Yamaha Apex uses Up/Down buttons on the handle bars to
control the Thumb Warmers and Grip Warmers. The Snowmobile Plug-In
ECU does not mimic this operation, rather it uses each of the ‘Up’ switches
to increase the settings, and then cycles back to the ‘off’ setting if the ‘Up’
button is pressed when the indicated setting is at maximum. When the
vehicle is powered up the initial settings are to provide 100% heat.
Customers can adjust from this default position.
Warmers will not operate below engine RPM of 1250.