Heated Grips wiring question

[Mike T]

I had a short (and melt down) on my RS heated grips. I bypassed the BMW heated grip switch and installed a hotgrips variable controller. The controller hooks up to +12V (I used the low beam yellow wire which I need to change since the low beam turns off when the high beam is on) and then into the black lead from each grip. The brown lead from each grip goes to ground.

 

I get heat out of them but not as much as I think I should. I noticed that the BMW heated grip switch has three wires to it. 1) Pwr 2)Goes to black leads on heated grips and 3) Pwr. The two power wires are for the high and low heat settings on the switch. I imagine that on the high setting that both power wires are connected to the grips. Does anyone know if this is the case and how this works? i.e. are both pwr wires 12v and and provide more amps so the grips get hotter? Any thoughs on why the variable contrller will not make the grips hotter?

[Ken H.]

On one of the leads there is an in-line resistor built into the factory wiring harness for them that provides the low heat setting.

[Mike T]

On one of the leads there is an in-line resistor built into the factory wiring harness for them that provides the low heat setting.

 

Thanks Ken, that makes more sense. So in other words if I hook up +12V power to my grips directly they will get as hot as they are going to get?

[Ken H.]

Yes