And most any other connector - seems to be a common flaw on any late model HD, every electical issue I've ever had boiled down to water getting somewhere it shouldn't, usually after a simple (non high pressure) washing with a hose and with the seat on.

 

if all else fails you can remove the throttle grip & pull out & R&R the TBW cable. on my '09 t/g i have though slach to do that.