Auto Function

[Will99]

On my 2017 Legacy, when I want heat, I press the Auto function, but the AC also comes on, and I have to shut that off to get just heat. Is there any way around this?

[Tehnation]

Probably means your temp inside is on the cusp of needing heat or a/c to regulate, something like 74 degrees F, 23 C, is average room temperature. So if the temp outside is around 70 degrees it will need both ac and heat to regulate temp. Either way, just cause the light is on doesn't mean its actually using ac, it just means it will if it needs to adjust the temp to what you set it to. Basically you don't understand hvac and you should leave it alone!

[Tehnation]

..... the keyword is "auto"!!! Turn off auto if you want to control your temp urself, otherwise let the climate control do its job. If you set it to a specific temp, it will apply heat or cold to reach it.... that's all there is to it, there is no magic. Your issue seems completely superficial...If its freezing outside and you hit auto and set it to 80 or max heat, and your ac turns on then you have an issue, but that's not how it works. Its probably more so to do with circuitry and how the auto climate control can't do its job properly if the ac function is not activated.

 

If you want just heat, then max out the temp gauge..... if you have auto on its probably trying to reach the temp your setting it to, maybe you need to set the auto temp higher.

[ammcinnis]

... the AC also comes on ...

That's normal behavior in FULL AUTO mode. The A/C indicator simply means "A/C Enabled," not "A/C On" and actively cooling. For best results, just leave the system in FULL AUTO mode, dial in the temperature you want, and let the electronic controller do the rest.

[upstater]

A/C does not mean cold air from the vents.

 

A/C runs year round (sporadically) to defrost/defog the windows in the winter, or cool and dry the air in the summer (full time in that instance), because in both cases it removes moisture from the air.

 

If your car is blowing cold air despite the temperature setting being high, that is because your engine oil isn't warmed up yet and therefore unable to provide heat to the cabin.

 

Put it in auto and leave it, you cannot micromanage the A/C anyway, because when you hit defrost in the winter or during a rainstorm to clear your windshield that god-darn compressor is still going to run because it helps dry the air to defog the windows while it defrosts them.

 

PS: you will eventually notice that even though that A/C indicator is off/on sporadically, when the engine warms up you will get warm air from your vents, assuming you have a temperature set that is higher than the current ambient air temp in your cabin.

Edited October 29, 2018 by upstater