Hi kezsir, I used this
Conectores de fiação sinal de volta da motocicleta, 4 unidades, adaptador de plugue para yamaha yzf r6 r1 r3 r6s fz6 fzs6 fz1 250 500 600|adapter plug|adapter 12vadapter yamaha - AliExpress
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I disassembled and removed the temperature selector leaving only the two wires that are fixed in the grip(resistance) and I
screwed the cover back. This two wires from the resistance I welded each one on a wire from the connector. The right grip, I only welded the two wires on the wires from the connector. You need know that there are two factory connectors, one for each grip and each factory connector there are two wires one for each wire from the resistance. When the resistance is correctly connected on the factory connectors the heater grips menu will be able.
If I wasn't clear, please feel free to ask any question.