Evaporator Drain Tube: Description and Operation
SYSTEM OPERATIONCondensate Drain
Condensation from the evaporator housing is drained through the dash panel and on to the ground. This drain must be kept open to prevent water from collecting in the bottom of the housing.
If the drain is blocked condensate cannot drain, causing water to back up and spill into the passenger compartment. It is normal to see condensate drainage below the vehicle.