Yeah, he's still around.
Ken in Detroit here. Unless there's another member named Ken in Detroit, that must have been me. I vaguely remember selling one (that happens as you get older). I'm glad it's been OK for three years, and wish I could help you with a replacement timer, but I don't have much in the way of parts. If I did have a replacement for you, I'd send it postage paid in a "magic minute". Too bad the GM warranty expired about forty years ago!
I hope you can repair it and/or find another one to use. Best of luck. I'll bet someone out there has one for you.