Just took my trailer out of storage.
The first thing I noticed was that the Faucet top wasn't there,
It was laying on the bed beside the sink.
So after major investigation, it seems that I did not open the faucet valves last fall when putting the trailer away.
The water in the faucet froze, expanded, pushed up the faucet top, and broke the plastic hold down screw.
Checked all valves, connections etc. very carefully, did not find any other issues, and replaced the hold down screw.
put some water in the tank and ran the onboard pump.
Found the aerator also had cracked, replaced it as well.
Checked external water supply, all working.
"Note to Self" open all valves next fall.
Hope this helps someone else.
Total Cost of repair $6.00 for hold down screw kit with O rings and an aerator.