We have a brand new Lacrosse and the water pressure is good in the kitchen and bathroom sinks but almost nothing in the shower, there's a shutoff knob on the shower head but its open and stil just trickles out.
Another place you might check is for a kinked hose. Find the access panel behind the shower wall and check the supply lines leading to the tub faucet. If either is kinked, loosen the fitting at the back of the tub faucet, straighten the supply line and tighten the fitting back up.
I had the same problem in my 2013 Blue Ridge. I took off the hose at the mixing unit and it turned out there are two rubber gaskets. One is a O ring and seals between the hose and the unit when you screw it down. Thee is a second one inside underneath the white plastic piece with a hole in it for the water to come through. The gasket is shaped like a cap with a half to 3/4 moon cut in it that acts as a water reducer I am assuming. I simply pulled it off leaving full hole in the rubber cap. Put it back together and I have plenty of water pressure now. I might burn through the hot water faster if I leave it full open but at least it is my choice now on how much water I choose to go through.
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