Condensation on range hood and air coming out behind cabinets.

Some photos would help us to be able to help you.

Is this a range hood that exhausts outside (roof/wall?) or just recirculates air into the room after going through a filter? If the former, have you put your hand over the exhaust outside to confirm that air is moving?

For the “condensing” issue, are you saying that when you’ve got a boiling pot of water on the stovetop/cooktop that some of the steam is condensing on the fan hood? That’s not unusual. Or are you saying that this condensation is happening just when the fan is operating, regardless of whether steam is being produced below it?

Assuming that the fan exhausts outside, if you seal the duct termination on the exterior of the house temporarily, does the airflow that you’ve described behind the corner cabinet stop?

Chris

Condensation on the metal surface of the fan isn’t an issue unless it accumulates to the point where it drips onto the cooktop below. Is that the case? That shouldn’t happen in a well-designed unit if the fan is pulling air at an appropriate rate. Maybe the damper on the external vent is stuck closed, so even though the fan is working the air isn’t exiting the building. Let us know what is the answer to:
“..have you put your hand over the exhaust outside to confirm that air is moving?”

If the damper is stuck closed and the installer didn’t seal the ducting between it and the fan properly it could be that air is being pushed out of the duct behind the cabinetry. That doesn’t explain why you’re seeing a draft there when the fan is not operating, though. That suggests that possibly the damper is stuck in the open position and allowing wind to push air into the house where it is again leaking out the ductwork behind the cabinet.

Chris