The heater stays on the floor will not go to defrost

You don't say the make and model and year of manufacture of your car. Come cars have vacuum controls for the blend door. Others have electric motors.

heater control could be faulty or vaccum to control unit is not sufficient or possible air duct abstruction not letting switch from floor to defrost.

If the heater is working correctly, and the air temp does not stay the same coming from different outlets, the problem could be a blend door under the dash. The blend doors direct air thru the heater core and out the vents.

go by liquid coolant and check ur heat and ac fan it might be stuck or broken

there is a actuator that makes a flap flow air out the defrost or the floor they work off vacuum . need to check see if vacuum hoses bad or broken .to get to actuator -the heater box under dash.

either a vac. supply problem or a broken heater box

Check for vacum at the heater control ports behind the dash and for vacum leaks. For safty reasons the
system is designed to go to defrost mode in case you lose vacum to the system. Hope this helps.

either the AC\Heater panel switch on your center dash or the heater box vent door is stuck or not operating. Most likely panel switch or disconnected \ broken vacumm lines at back of switch

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The "blender" would refer to the blend actuators that change the flow of air from floor to vent to defrost or combinations. Properly working blend doors will allow you to direct air to the dash vents, the floor, the defroster, the floor and defroster or the floor and dash vents. If it is not working the heater will still work but you will hae no control oer where the air flows.

When the engine is cold,check the coolant level.

Make sure it's on max.

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A coolant system should be flush every two years.

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If you did a coolant flush recently then air pocket can be the cause of the un-even heating problem.

The DIY method is to drive you car onto a ramp or a steep hill.

Iet the engine cool off and top off the coolant tank.

Set MAX heat + MAX fan

Let the engine ran for 20 minutes wih the cap off and the trap air will escape from the coolant reserve tank,

Check coolant level and top off coolant when the engine cools down.



A shop will charge $75+ for this but using an air operated excavate tool!

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A car with over 90K miles may experience linkage problem to the heater control valve.

The heater control valve (near the firewall) may be stick over time.

Open the hood and move the heater to max and min. Back and forth.

Clean and lube the linkage with WD-40 to free the heater control valve.

If it's a vacuum type heater control valve then cash for leaky vac. hoses.


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Move the fan switch back and forth to re-new the electrical conductors.

Pass a vacuum over the control panel to prevent dust build up behind the console.