In the last couple of flights, my 1987 A36 Bonanza is exhibiting a curious problem. Flaps go to approach (and the light comes on) setting normally, but on final when I move the flap lever from approach to landing position, nothing happens. When I move the lever back full up and immediately back full down, the flaps extend to landing position, but the light does NOT come on. On the ground however, everything works normally, even with some resistance during flap extension to simulate aerodynamic loads. My mechanic has been looking at all the switches everywhere and there's no obvious problem.
Any thoughts on what the problem might be?