Left & Right in the directions below, mean while you are sitting on the sled.
To install Plug & Play ThumbBoost Kit on most models you simply need to locate the following 2 factory connectors on your sled:
Brake Connector (Has Blue/Red & Green wires to it)  (In main boot on Apex/Attak & Right boot on most others)
Thumb Warmer Connector 
  (Has Black & Teal Blue wires to sled) (Black & White wires with cloth covering to Thumbwarmer)
  (Thumb Warmer connector is in rubber boot at base of bars on Apex/Attak & Left boot on most others.)
Unplug Brake connector & Plug ThumbBoost Connectors with Blue & Green wires into open Brake Connectors. 
Unplug Thumb Warmer connector & Plug Connector from ThumbBoost with Yellow & Black Wires into connector with Teal Blue & Black from harness. 
Plug Thumb Warmer connector (White & Black wires) into connector with Green & Brown wires from ThumbBooster. 
Even your power is already connected with these simple plug-ins! 
If there is a mini-blade Blue 15A fuse included in your package, replace the SIG fuse on your sled with the 15A fuse. 
Put the old fuse in a spare slot in your fusebox. 
It really IS that easy!     Let us know how you like & check out The YamaHeater, YamaHeater Booster, Starter Saver & Trail Jamz!  
Rock  : )
As always can Call/PM/Text/email me with any questions.
Your fuse box is near your battery and/or reverse mechanism.
The factory connectors you need are in rubber boots at, or near the base of your bars, behind your headlight.
All your factory settings on your Thumb Warmer, (1-8 Bars & Off) are just like they were prior, EXCEPT they will all be warmer!
Enjoy your Warm Thumb!

Quick Connect Plug & Play Kits to make install a SNAP! 

Fast, Easy, & WARM!