My 2011 242 has all 3 pumps behind the carpeted cover on the back wall of the left rear locker. Guessing the 2012 would be the same. I put 750's at first and then 1100's now in both rears on my 242 and reprogramming the timer was easy. I think the 750's were about 6 minutes to fill. 1100s are 10 or 11 minutes. I set the timers at a longer than that run time, started filling and timed them with the stopwatch in my phone. When full shut the pump off manually and noted the time then reset the timer in the VISION to match. One and done.

Kevin