My 2004 trillium
also has a DC only fridge
(Nova Kool). If it's the same as mine it's already wired for a fan. There is a +- spot you can plug one into and it will cycle with the fridge
. There should be a wiring diagram on the back of the fridge
I added two fans recently and they work fine. Camping in Radium BC last week it was 40 degrees (C) and the fridge kept everything cold/frozen. It was on almost the entire time during the day so I'm not sure the fans helped much. However keeping the fridge side shaded helped drop it's cycles significantly. Shade or sun the fridge temp was good so the fans either helped or the compressor just works well regardless.