Water in cabin filter area of 9900

[SquareOne]

Check for a drain being clogged. That area is going to condensate because of the ambient air being pulled across the evap coil.

- There will be a drain at the bottom (usually at the lowest point in a corner). Those drains will often get clogged from dirt and debris (much like whats in there now). When you bounce around down the highway the dirt falls down, collects at the bottom, and causes the drain to clog.

- If the A/C lines are sweating, that's fine....you should still see a consistent drip out of a particular area under the truck. Thats where you'll find the drain.