Last weekend, I went on a nice cruise on the Blue Ridge Parkway. Most of the way, I kept hearing this new squeaking noise behind me, in the vicinity of the tension cables.
A day before the trip, I tightened the cables to stop the attachment bracket from rattling, which worked. During the ride this new squeaking noise bothered me, so about half-way I stopped and opened up the top and discovered that I had latched the fabric rod with the foam padding under the end of the rod, at both ends.
I pulled the foam out and let it rest along side the fabric rod, and presto, no more squeaking!!! It's amazing what the smallest things can cause.
Thought this might help someone else someday.