Q: heater will only blow warm air , defroster only blows cold air , and cant get selector switch to function on floor only setting.

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i recently flushed cooling system and replaced thermostat and radiator cap. have burped air from cooling system, i think.

My car has 240000 miles.
My car has an automatic transmission.

You are having trouble with the A/C evaporator temperature and the mode doors of the evaporator case. The doors and temperature is controlled by the A/C controller control head unit and the doors are servo motor controlled.

You also have a temperature control sensor that may be not sensing the correct temperature. You will need to have an A/C system diagnostics done to see if you have one or more problems with the blend and temperature doors.

If you decide to get his fixed, consider getting some help from a certified mechanic, such as one from YourMechanic, who can come to you and perform this diagnostic and repair.

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