I know this will sound odd check Ign. switch I couldn't remove keys and had switch repaired and it started working again. go figure?
The heater core has failed.
Yes, gnats can come out of dirty air vents. Gnats can actually come from anywhere. They are very pesky creatures.
a person satnding in the way of the vents
If air in a 1999 Jeep Grand Cherokee blows but doesn't come out of the vents, it could be due to a malfunctioning blend door actuator or a clogged or broken duct system. The blend door controls the airflow direction, and if it's stuck or broken, air may not reach the vents. Additionally, a blockage in the air intake system or a failure in the HVAC controls could cause this issue. Inspecting these components can help determine the exact cause.
heater fan broken.
The heater may not be on - but the fan still blows air through the vents when they're open !
the middle vents only supply air from the ac unit using a separate in dash fan. the floor and defrost vents come only from the heater
something has to be blocking the vents.
Heat and steam coming from the dash and air vents after replacing the water pump means that a hose is hooked up backwards in the new installation. The heater is actually taking on water when it is supposed to only take on hot air.
leaking ducts allowing air into system.
Return air vents.........
heater on at idle and will not blow warm air. when moving it blows the warm air from the vents. what will cause this