Welcome to the FF. I still own the second of two TH's I bought. They are wonderful machines... TH's demise was not due to the quality of their product.
Do you know that the switch is good? Dirt on the contacts often prevents the switch from activating the seleniod to kick the hydraulic cylinder. You can test whether it is the switch by shorting the contacts with a screwdriver.
If shorting it fixes the issue, replace the switch. You can buy "boots" at a good electronics store which fit over that type of switch and greatly prolongs their life by keeping dirt/sawdust out.
If not it is fairly likely there is a break in the remote wire. Most breaks I have occur within the first 2-3 feet from the remote box. Another place to look is where the hanging cables would rub on the head as the carriage is returned. If you wiggle and twist the remote box and cable with the switch engaged and it shows sporadic signs of life, it is a broken wire.
I also know there is a screen door opener which allows the arm to follow the contours a of the log, maybe that is shot. I am out of town and will need to get back home to look at mine as I don't remember exactly how it functions.