Many times the switch needs taken apart and cleaned. The crap grease used often hardens and stops things from working. I hope you have the "RAVE" manual to use for further exploration..[It's available on-line for free, and is a must have for these vehicles.]
'99 Disco II
'95 R.R.C.Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S
Thanks, I will attempt a dismantle and cleaning, check fuses, etc. The upper back rest control still works so it is only the one forward/backward control that is not working. I do not have this RAVE manual you are referring to, is it easy to find via a Google search? I will try that first.