One easy way to tell is crawl under the rig and look at discharge piping and dump valves are and see if they have a heat wrap if they do you have a tank heating system installed.
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Retired Navy
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho