One is by the fresh water tank on the driver side towards the rear and the other is on the passenger side in the pass-through. You have to take the two screws out to get into the compartment, same as getting to the hot water bypass, only on the other side. At least that's where they are on my 26.5 RLS.
2012 GMC 2500HD D/A Crewcab
2012 Jayco Eagle SuperLite HT 26.5 RLS
2009 Crestliner Superhawk 1900
2013 Polaris Sportsman 550 EXP
2008 Polaris Sportsman 700 X2