When you say sinks, I take it you mean the bath, kitchen, etc. Are you getting any water or just not hot water? Lets say you are getting cold water from both the hot and cold side of the faucets. To me that means you have a winterizing value in the wrong position. This link should help, as there are 4 different models of Sundancers I did not know which one to look at.
https://winnebago.com/Files/Files/Wi...m/Plumbing.htm
Other side, Are you not getting any water at the faucets neither hot or cold from either side. If thats the case you may want to look at the screens on the faucets they do become clogged and will stop the flow of water.
Heres another good link to help with all things about your rig
https://winnebago.com/owners/owner-resources