The A/C evaporator housing case (or HVAC unit) organizes cabin climate control. It contains the blower motor, evaporator core, heater core, and the blend doors that route air. The case has a drain port at the bottom. This port lets condensation escape under the car. If the drain clogs, water will fill the case and spill onto the passenger floorboards.
Mechanic Glossary
A/C Evaporator Housing Case
The plastic box located under the dashboard that encloses the evaporator core, heater core, and blend doors.
Frequently Asked Questions
Behind the glove box and center console, tucked deep under the dashboard.
A clogged evaporator drain tube. Dirt and leaves block the drain hole, causing condensation to backup and spill into the cabin.
In most cars, you must remove the entire dashboard assembly to split the plastic housing case open, which is a major job.