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Partially Lit AC Button Means ...?

Partially Lit AC Button Means ...?

After 8 months with my 2018 Model S100D, I still can't understand how the climate control system works! Sometimes the AC compressor button is lit blue (On), sometimes it's white (Off), and sometimes it's light blue (Huh?). In AUTO mode, the AC cooling always turns on immediately after I enter the car in the cold winter months but never turns on in the hot summer months - requiring me to override the setting every time I get in the car. (It's not because the compressor needs to be on for defogging). For example, it's 48 degrees right now in Chicago and my set point is 72 degrees. As soon as I enter the vehicle, the AC cooling starts blasting cold air until I intercede by manually turning off the AC and manually raising the set point to something above 80. Only then, will the cabin begin to warm even after 30+ minutes of driving. The opposite happens in the summer - as soon as I enter the car, the heat starts blasting until I manually lower the set point (from 72 degrees) and manually turn on the AC switch. Is my climate system wired incorrectly? I'm just noticing the partially lit AC button in the climate settings and wonder what it means (no, it's not in the manual). Ironically, if I set the cabin temperature to match the outside temperature, only then does the cabin stay comfortable. That is, since it's 48 degrees outside, I set the climate to 48 and I'm comfortable throughout my trip. I'm leaving shortly on a four week road trip out west and can't imagine setting my temperature to 100 degrees just to stay comfortable. There are a lot of bright minds in this forum - who has a thought as to what's happening here? Thanks in advance!

TeslaTap.com | 2019年5月28日

I don't have a lot of temp extremes. Typical is 60 to 80F around here and auto works well for me - rarely override it. Perhaps the battery gets priority on some temp extremes, but the cabin heater is independent of the battery heater - so in cold weather is shouldn't matter. I assume you don't have Range mode on? This greatly reduces the effectiveness of HVAC to improve range slightly.

My understanding is the buttons go to light-blue when auto is selected. When you override auto, the specific button turns to normal contrast and you can toggle it on or off.

p.c.mcavoy | 2019年5月28日

@rweggert - So I've seen a little more temp extremes than TT, like low single digits to pushing triple digits F. A couple comments over the last 3 years and based in central Indiana, so not that far south of you.

Some of the initial reaction of blowing hot air when it's hot and AC expected to be on or blowing cold air when it's cold outside is likely just the fact that the HVAC doesn't respond instantly combined with the ducting being filled with chilled when cold and hot/heat soaked air when hot that takes a little while to get purged.

The other factor when cold is that the AC system is also used to dehumidify the air/interior cabin. That's where I find that the auto setting in say temps in the lower 40s when you're wanting hot air feel cold. I will manually turn of the AC in those conditions as it makes no sense to me to be chilling hot air to dehumidify it if I'm not getting window fogging. I manually turn AC off in those conditions as much for total energy efficiency (lower Wh/mi) as much as my comfort level.

If you've not figured out, you can manually turn off AC but still keep the fan control in auto mode. The way I do that is after manually turning off AC I set the right scroll wheel to fan speed. Once it's on speed, if you press the button, you'll see "auto" pop up in the dash display below the speed and fan will go back to auto control. You can then proceed to switch the scroll wheel back to temp or something else if you wish and the fan will stay in auto provided you don't make another manual adjustment on the main screen.

redacted | 2019年5月29日

My climate control works by leaving it on auto and it's fine. Chicago.