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Pre-2020 cars have wiring for a rear ac button
- Thread starter smatthew
- Start date
Do the rear vents not auto on when seat belts are clicked in? I thought it does. Or it'll remember setting and turn on when clicked in. I had kids back there and vent would turn on throughout my trips.
There's a 91.5% chance you'll explode
If you hook it up and it doesn’t work right away, it might start working after a routine software update.
Yeah, if you remove the rear air vent, the cable that runs to the USB ports has another branch of it that is tucked back in the console. Tracing the wire diagram shows it goes to
Rear HVAC Control
X501-1 High-Side Drive Button Signal & LED
X501-2 Ground Return
Rear HVAC Control
X501-1 High-Side Drive Button Signal & LED
X501-2 Ground Return
Oh they totally do automatically turn on when the car senses a weight in the rear. I can only assume some engineer included the button BEFORE they knew about the seat sensors. I've never seen a car with the button installed, but it makes me wonder.... did they ever write the code for it? And if they did, did anyone ever bother removing the code? I can't imagine removing the code would be a priority since it would literally never be invoked unless someone starts messing around like me ;-}
I think the opposite is more likely. If it happens to work now, there's a good chance it might stop working after someone at Tesla does a code review and wonders "Why is there code for a rear AC button"
Then again - maybe the button triggers the same code as the on screen button.
Sounds like I've got a weekend project.
If I disappear from the board... you'll know why. I honestly would have thought the probability was the car exploding...... but who knows how buttons work!
android04
Active Member
No it won't. I came across this unused plug when I made some modifications to my center console. It shows up on the service manual as "Rear HVAC Control" with the blue wire as ground and the white as "button signal and LED". I tried shorting them with the HVAC on and looking at the screen to see if the rear would start/stop blowing air. Nothing. Also tried putting an LED on the wires to see if it would light up with the rear blowing or not. Nothing. So I'm guessing that is either not active or not connected at the MCU end either.
By the way, my car is a March 2018 build and I also found 2 unused plugs under the frunk tub towards the front of the car. One is 2-pin and the other 3-pin. I took pics of them, but haven't been able to identify them (haven't tried hard).
I think you're confused. No model 3 sold to the public had the physical rear AC button. Someone designed it in the harness so it was a possibility very early on, and Tesla just didn't bother removing it from the center console harness until 2020.
