Hi to all, here the final update on our former jack problem.
The one jack that stop working all together ended up having a small corrosion spot on the blade of the fuse. after replacing the fuse, the jack started working.
We also had a dilemma with the front jack. That one had broke the weld to the frame mount.Evidently they at the factory/ dealer only tack welded the one jack bracket with 2 small stitch welds, about 2 inches long. Had a mobile welder come to the coach and re welded the bad one and did some minor welding on the other 3
all is good.
Thanks again for the responses