Alright Greenthumb, don't let them go black!
Can't answer all your questions, just a few. On the throttle end, there's just a slack wire that goes along for the ride when you twist it. No slider or slip ring thing. The switch just tells the ZFE (ECU) whether it's off/lo/hi then the grips are supplied voltage accordingly. They're wired parallel, often one fails while the other carries on. The right side will be hotter because it's somewhat insulated by being mounted on plastic with an air gap between it and the bars. The left side is solid to the a
handle bar and tends to heat up that end of the bar too so it feels cooler. Not like your sled where they're both the same. Never heard of both acting up together. If that's true then there should be a code thrown. You on warranty? GS911?