I have an 86 1680 with the same problem. It works when cold. Seems like when it warms up is when I have problems. I've replaced the limit switch for the extension which I thought helped, but this year it is doing it again. Also, the last time not only the auger, but the reel up and down, fore and aft did not work. Next morning, it all worked fine. The solenoids, top and third, farthest from machine are energized. Company mechanic can't figure it out either. Hope someone has solved this problem before. Thanks