Ok...when you turn the defroster on it will work and blow out hot or cold depending on the temperature you have it set on. However, when you turn the defroster off and just try to let it vent into the car it works some of the time. It was making a weird noise and stopped blowing air out. I tried it again the next day and it worked. This has been happening off and on the past few days. When it's not working, I heat the car with the defroster on. Is the blower fan or something fixing to go out? I'm pretty sure the ac still works, as in gets cold, it just doesn't won't to blow out all the time just like the heat. The blower fan when it was making noise sounded sick, you could tell it was fixing to go out. Why would it be working now?
My car has 122720 miles.
My car has an automatic transmission.
Hello - your symptoms suggest that the HVAC blower motor resistor has failed. The blower motor resistor limits fan motor speed for the Low and Medium settings, but is not involved at the Max setting. Since defrost on most cars uses the Max fan setting, the blower would work for Defrost but not for Heat or Vent. I recommend a fan not working inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, confirm this diagnosis, and give you an accurate assessment of damage and cost estimate for repairs.
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