Not familiar with how the Ranger cooler works, but on my triton, the cooler drains directly into the bilge, and does not have a plug. As a result, I end up with water in my bilge.

Could this be the same thing for you?

One thing, I never get enough water for my auto bilge to kick on, but I do routinely turn my bilge on just to be sure, and often, especially on really hot days, pump out some water.

I hope this helps,

Tight lines and God Bless

Danny