I can hear water moving behind the passenger dash when I make turns and brake. I really think its condensate from the A/C. The truck sat while I was deployed to Iraq and I don't remember hearing it before I left. My question is....WHERE IS THE DRAIN! I have talked to people that make it sound like it is RIGHT THERE on the firewall or underneath but I looked all over for it. I think its clogged and needs to be blown out.

Thanks!!

Rich

Sounds more like coolant in the heatercore. This is common for these trucks. Check you coolant level. I dont know where you are, but unless it's hot there, and you'r running the a/c, it wont build up fluid.

Is this sound a warning of the heater core going bad? Or, is the sound normal to hear? How do you make it stop?

yeah, my level was low so I filled it. It's still pretty cold here in Virginia and my heater is blowing good and hot. Now worries or just the beginning????

Well, if I were you, I'd be wondering where the coolant went to. If there is no coolant on the driveway, it's not in a good place.