Thetford flush issue

I never had any cables in my Thetford. The underside of flush handle is hollow with little boxes. Two protusions sticking out and into a box area control flush valve and water. Thetford suggested a new flush handle when I described problems with them. I pulled off the handle. Thetford describes how on their site. After looking at the handle design I decided to replace it with a Dometic toilet. Easy replacement and no trouble since.