I'd suggest that you turn the pump on, open a faucet and follow your ear. It will be in the bottom of a cabinet behind a removable panel. If there's a filter. it'll probably be there also...you should plastic wrench that fits over the canister for removal.
On my two previous Wildcats the pump was in the side front storage compartment. Like Dave said, put water in the fresh water tank,turn the pump and a water faucet on and follow your ear. Since you have a Sterling you probably have (or it did have) a tankless water heater which means you don't have a water filter.
Hopefully a fellow Wildcat owner will respond to this post soon.
Bob and Joyce
2013 CC Silverback 29RL
2010 Ford F250 XL Crew Cab 6.4 liter diesel
ATU Local 788