Got 3-flash code for pressure switch problem on my trane xe90 system (~15 year old). The inducer fan runs with normal sound. Can see the turning of fan. Opened the front tube to pressure switch and saw water dripping out. Dirty brown rusty water also came out of the front hole on the pressure switch. Opened the back tube to pressure switch. Can feel air coming out of this tube but don't know the pressure. I suspect the pressure switch is dead. Any suggestions for this issues? Thanks.