campigloo,
I replaced my outside connection for my black tank flusher about 4 years ago when it started leaking. Actually, my own fault because it cracked over the winter.
More than likely, when you replaced the outside connection, you disturbed dirt build up in the lines and some of it broke loose. Now that dirt (or skum) is blocking the jets inside the tank.
Either that, or your black check valve under your bathroom sink is installed backwards.
Either way, go under the sink. Look for the 2 water lines that come up from the floor. Remove the black check valve. Then, with a good shop vac, tape a hose to the line that flows into the tank and turn on the shop vac. This will suck any debris that might have broken loose from the inside of the pipes and suck it back out, also free up the nozzles inside the tank.
If you used any plumbers putty on the outside connection, chances are some of the putty might have oozed inside the pipe and when you turned on the water, it broke free. If so, it clogged the black check valve and its now ruined.
So, removed both lines from the check valve and try the shop vac on both lines to make sure they are free. When you feel they are free, then (I know this may sound awful but) try blowing real hard through the pipe going inside the tank and if it's now free, the air will pass. If not, it's still clogged at the jets inside the tank.
By the way, this is how I now winterize the black tank flusher. I remove the check valve and simply blow air into the pipe from under the sink.
I made the mistake once of using a hose in my yard that was laying on the ground and attached it right up to the flusher before letting some water run first, rinsing the hose out first. I immediately knew I made a mistake because the end of the hose had dirt on it. That little (tiny little bit of dirt), by passed the check valve and clogged up the jets immediately inside the tank. I freed them up using the the method I just described.
FYI, Mine is a 2013 Outback 298RE.
