brossie

I have water dripping from a seam between a/c tubes under the dash on the passenger side. When you are looking at the tubes, they are just to the left of the fan. I know this is from the water not properly being drained but can anyone tell me what would cause this or an idea on how to fix it? I thought maybe a line or the a/c filter would be clogged. Does anyone know how to check these and where the a/c filter is? Thanks

Ben