My shower on my 1012 and my 2013 have this problem. Sometimes it's BURING hot sometimes it's ice cold. Overall, we rarely use it because it either burns of freezes people.
My air heater on both my 2012 and my 2013 MC's are very poor. No where near the warmth of my Moomba. I actually plugged the passenger cup holder vent because the air was always cold and no one really can use those heaters anyways.
Overall I love my boat and all the options but these 2 options are not up to par in my eyes. Both should work better.
2013 X-30, 6.0L with 2500lbs of ballast and 500 lbs of lead.