Hi Spinners. I just went through the same thing looking for a slide controller for my 2004 Minnie. My mobile repair guy said I'd be lucky to find one, I didn't.
He said he could build me a double on off switch to make it work. He did bypass the controller just to make sure the slide motors were good and they were.
When he comes back I'll take some pics of what he comes up with. I think he will use the old controller and just jump around it somehow.
PM me if you'd like some pics of his work/switch. He made it sound pretty simple.