This is so silly, but my coworker and I had a fervent disagreement. He told me most cars today use vacuum to actuate the hvac blend doors. I told him he is out of his mind. HVAC blend doors use stepper motors to change the blend doors. Who is right? I can’t find obvious answers on a cursory search on google.
AC blend doors vacuum or motors?
- Thread starter Kurtatron
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Most are motors. Vacuum isn't as common anymore except some base entry level trucks with the old 3 knob AC.
In my 2005 Taurus it’s a motor to adjust hot and cold using a flapper. It’s vacuum to change the ducts from the floor to the dash and to the defrost.
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Late model cars. He told me his 2020 Miata uses vacuum.
BMW has used stepper motors for a long long time.
'86 E 28s had cable operated flaps. '87 up were stepper mtrs
According to the Mazda GEPC (Global Electronic Parts Catalog) there is no vacuum going to the AC box whatsoever, all motors.
He needs to get better acquainted with his MX-5. This is the blend door actuator (with stepper motor) for a 2020 Miata.
In 2000 the Ram went electric (for temp only), giving birth the Heater Treater not long after. Before that it was cable, though.
People talk about "blend doors" but some mean temp, others mean direction of airflow, and some mean both.
I'd say vacuum for direction of airflow hung on longer. I think my '19 JL still uses vacuum for defrost/vent based upon weird whistling/groaning noises from the dash at altitude when I do anything with climate control.
People talk about "blend doors" but some mean temp, others mean direction of airflow, and some mean both.
I'd say vacuum for direction of airflow hung on longer. I think my '19 JL still uses vacuum for defrost/vent based upon weird whistling/groaning noises from the dash at altitude when I do anything with climate control.
Ford Panther chassis' (Crown Vic, Grand Marquis, etc) use vacuum motors for the fresh/recirc and floor/defrost actuators but a stepper motor for the blend door.
I would venture to say that they are more likely cable operated than vacuum these days, that would be for manual HVAC. Auto climate control would be all step motors.
I would expect everything to be completely electrical as of at least 10 years ago.
I would say electric. I know on my 98 Chevy trucks, all three doors have electric motors.
my 96 Honda Civic is an electric motor that moves the blend door and the recirculate/fresh air door. No vacuum on the Civic.
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