I really appreciate learning the probable reason for my Rad controller failing. I have one question and then I can take action to fix the problem. My question is How do I know if my failed controller is version 35A? The order sheet only says "Controller - RadCity 5 Plus ST" Rad tech support (Chat) is not able to tell me the specs of my controller.
Thanks again for your help.
Carl

Thanks for the suggestions, Inoxa.
How do I check out Area 13?
Where can I learn about headlight upgrade?
Sorry for the newbie questions. I'll search the site, if that's the best way.
Carl

Help Needed!
I own and love(d) a rad city 5+. It is 18 months old. Had the usual problems, and loved the bike.
BUT . . .
After one year, the controller failed, confirmed by diagnosis under guidance from rad tech support. Replaced the controller. After only 6 more months, the new controller failed.
I'm hesitant to buy another controller from Rad. Pricey, and no way to know if it will fail again.
Rad customer support (no way to talk with Rad tech support) says, sorry your out of warranty. No explanation for why two controllers fail. No confidence that a third controller will work any better.
Any advice is welcome and appreciated.
Carl