1999 Dodge Ram where to find?

You Have mentioned:
It sounds like there is water in the dash sloshing around. I am sure it is the heater core. Where would I find the relief hose to empty this water? Also, if it is clogged how and what should I use to unclog the relief hose?

Have you found the solution yet. I am having the same sound come from under my dash in my 96 Ram 1500. When I turn corner I can hear it. But now I can hear it as I press the gass-peddle to take off