MrSmithers

I should've mentioned this is for a 2007 Centurion Avalanche.

I need to replace my blower motor, it's making horrendous noises. When I look at the vent piping, I'm not 100% sure it's all hooked up correctly. Here's what I have: #2 drops down to the bottom of the engine block (this is where the air gets sucked from), air flows through the blower motor (white) and out pipe #1 and blows to the forward facing vent on the right side of the boat. #3 goes to the forward facing vent on the left side of the boat but is not connected to anything in the engine compartment (I assume this one allows fresh air to be drawn in when the blower motor is on?) 4 is an open double vent to the back of the boat but has 2 4" collars (see second picture) that could possibly be connected to vent pipe. Since I'm going to replace the blower I'd like to set it all up correctly. My question is ... is this all correct? Or did the previous owner connect/reconnect some pipes to make it all work?

This is my third summer with my 2007 Centurion Avalanche C4 and I still can't for the life of me figure out what this thing is for?? Its mounted on the inside of one of the rear lockers. Anyone know what it's for? Fetzer valve maybe?