Turning on rear vents for AC

[Goodtohave]

I noticed that the rear AC vents worked when someone was in the back seat but otherwise couldn’t manually turn it on.

I often have my dog in the back so wanted to figure it out.

At first I thought it was the occupancy sensor but it is just the seatbelt...so buckle it put AC on Auto and it works (not on manual)

Maybe everyone knows this but wanted to share...

 

[animorph]

Sounds like a faulty sensor. This says the seatbelt is at least one sensor:
Turning on rear vents for AC

Might try fooling with the seatbelt and see if that rationalizes your rear A/C.

 

[Tz00]

Did you turn on the vent via the button on the lower right of the fan screen?

 

[swaltner]

As @Tz00 alluded to, you need to Owner's Manual (page 104 of the 2019.16.1.1 version - the Adjusting Climate Control Settings section)...

 

[Goodtohave]

Sounds like a faulty sensor. This says the seatbelt is at least one sensor:
Turning on rear vents for AC

Might try fooling with the seatbelt and see if that rationalizes your rear A/C.

Nothing is faulty if no one is in the back the vent does not turn on so I buckle a belt and it turns on the vent when I drive with my dog in the backseat .

Not sure why everyone thinks something is wrong and is arguing...

It is just any easy way for me to turn the rear vents on, dog jumps in I buckle a belt.

Thought I would share that’s all.

 

[dsvick]

Nothing is faulty if no one is in the back the vent does not turn on so I buckle a belt and it turns on the vent when I drive with my dog in the backseat .

Mine come on without the seatbelt being buckled, my dog is big enough to trigger the seat sensor though so maybe that is enough to let the car know someone is back there.

 

[Goodtohave]

Exactly but 18lb like mine does not, I also thought if she was heavy enough the walking around may confuse it so glad buckling works

 

[jjrandorin]

Nothing is faulty if no one is in the back the vent does not turn on so I buckle a belt and it turns on the vent when I drive with my dog in the backseat .

Not sure why everyone thinks something is wrong and is arguing...

It is just any easy way for me to turn the rear vents on, dog jumps in I buckle a belt.

Thought I would share that’s all.

Does pushing the button to turn on the vent as detailed in the manual by the person who posted it not work? Genuine question, I dont have people in the back (or pets) so i dont use that feature but I did read about it.

What I am asking is, DONT go in the back and buckle the seatbelt in... simply push the button on the climate screen indicated in the manual (#5 in @swaltner 's post above). Does that not work?

 

[Goodtohave]

I usually just use auto, when you push the button the floor vents turn off from what I can see.

I prefer just pressing auto and clipping the seatbelt if I want the rear vents on for the dog

 

[Eugr]

Well, it's not just the seatbelt, it's a bit more clever. For instance, I have a car seat at the back that is secured using the seatbelt. If my toddler is not in the seat, the rear vent is not working, but once I put him in it starts blowing.

 

[Goodtohave]

It must be a combo of both the seat belt and occupancy sensor.

Rear vent was off, clicked the belt it turns on, maybe it knows your belt was clicked before the car woke up?

Who knows, it can be a bit random...But if I buckle when the car is awake it seems to turn on.

Dog loves the air in her face

 

[WilliamG]

In my car the rear vents never turn on or off unless I manually turn them on or off. Are you guys sure there’s some sensor that does this automatically?

 

[yumcha]

In my car the rear vents never turn on or off unless I manually turn them on or off. Are you guys sure there’s some sensor that does this automatically?

I feel like I only seen this work when I have had it set to Auto.

 

[WilliamG]

I feel like I only seen this work when I have had it set to Auto.

Ahh. I never use Auto.

 

[StealthP3D]

I feel like I only seen this work when I have had it set to Auto.

That's correct, when the A/C is set on "Manual", the rear vent is controlled by the rear vent on/off button, when on auto, the rear vent in the front console armrest blows cold air when it senses people are in the back.

However, I did notice a nice flood of cold air comes out underneath the two front seats even when the rear air conditioning is turned off. I *like* having cool feet. Does everyone's Model 3 do this as well or is mine broken? I do like the cool air but I'm not sure if it's supposed to work this way.

Test conditions:

A/C on manual, mid and lower airflow enabled, fan on setting "7".

 

[hugh_jassol]

Ahh. I never use Auto.

Curious... why? Every car I've had for the past decade I set it to "70" and auto. Works year round.

 

[Goodtohave]

Kind of like the thermostat in my house, hardly touch it.

I get in clients cars, super high end in the winter the heat is set at 36 degrees C, so odd.

 

[WilliamG]

Curious... why? Every car I've had for the past decade I set it to "70" and auto. Works year round.

Because I don’t always want AC or heat on, or I drive with the windows down a lot.

 

[wwarren]

Kind of like the thermostat in my house, hardly touch it.

I get in clients cars, super high end in the winter the heat is set at 36 degrees C, so odd.

When I picked up my old car after having service done, or when I get in a rental, the AC is always set as cold as it will go with the fan on high, like that's going to cool it down faster. People have a misunderstanding that they are affecting the temperature of the air being blown.

 

[ElectroScoot]

I noticed that the rear AC vents worked when someone was in the back seat but otherwise couldn’t manually turn it on.

I often have my dog in the back so wanted to figure it out.

At first I thought it was the occupancy sensor but it is just the seatbelt...so buckle it put AC on Auto and it works (not on manual)

Maybe everyone knows this but wanted to share...

Thank you!
The weight sensor does not detect my toddler in the back seat so I ALWAYS have to manually turn on the rear vents. This is a good work-around (for those of us that use AUTO climate).