When we remove the back, we see lots of wires, but have no idea which wires lead to the back element. We cannot see where the element is. What do you mean by the element "below the floor"?
Thanks, we found the element. It's actually cracked 'open' (?) along one of it's edges. Our friend is coming over with a multimeter, but it seems obvious we'll need to replace the element. Thank you for the link to order a new one.