Koz1614

Hey guys,

One more issue, sorry The last two mornings I’ve noticed my AC not getting as cold as it does in the afternoon. I usually keep it on 68..after 30 min of driving in the afternoon I have to turn the fan speed down because it gets pretty cold! The last two mornings, with the setting all the same as they are in the afternoon (68, recirculating, AC on) it’s just clearly not as cold. Any reason? Maybe the car dials it back as it is not as hot out. 68-70 degrees in the AM vs like 85 in PM. I’m stumped on this one. I took the thermometer last night and it was blowing at 40 degrees so I don’t think it’s a charge/leak.

Sasnuke

If your target temp. and the ambient temp. in the morning are that close together, chances are the AC isn't running much at all...but having said that you should not feel hot because you're ok with 68 in the afternoon.
In the afternoon when it's 85 out and the target temp is 68, then the AC would be constantly running, since the gap is 17 degrees.
Although I wouldn't expect the humidity to be as high in the morning as it is in the afternoon.

Are you using Auto mode? or have you tried Auto mode yet?

Koz1614

Im not on auto mode no. So if the target temp and ambient temp are close, the system will pull back the AC even if it’s not on auto mode?

Sasnuke

It's not so much pulling back as it's cycling the AC.
When the AC light is on, it only means the system is active...the ECU still controls the cycling of the AC to reach/maintain your target temp.
So if your ambient temp and target temp are really close, the AC will not cycle on much, or at all...so you'll never get that "cold" feeling from the vents.
If outside is 85 and the target temp is 68, the AC is mostly cycled on, if not constantly on...that's why it feels like a fridge freezer right at the vents...to the point where you mentioned you had to turn the fan speed down.

Auto mode is more like you set it to 68 and no matter the season or time of year, the HVAC system will always be trying to hit that target.
So in the summer it will run the AC and in the winter it will provide heat, without you having to touch/change/click anything else.
It will select what you need (hot or cold) and adjust fan speed accordingly...basically all the things you are doing manually.

Personally I've been driving way before Auto mode was a standard thing, so I'm old school and do it manually like yourself...I guess I just prefer it that way.
Also I'm a big fan of opening the window and roof, so I really only use the AC when it's stinking hot out. Winter you need the heat here...there's no getting around or away from that.

arentz07

I'm definitely an Auto mode fan. Maybe that's partly because this was my first vehicle to feature any sort of automatic climate, but either way... I do feel that, in the mornings when it's cooler, I still feel a warm sensation at times. I think the fact that I don't have cold air blowing on me contributes to this. My target temp in the car in the summer is 72, and the past several days the ambient temps in the morning have been in the low 70's.

Koz1614

@Sasnuke

I did a test this morning to see how much of a variance there is and the results are pretty surprising. Used a digital thermometer and put the probe in the middle vent.


Ambient outside temperature 67

1. First drive after taking car out of garage - air on 68, Fan level 3, recirculating. (Temp range low 57 - high 72.)

2. On the same drive lowered all the way to ‘Lo’ setting, fan 3, recirculating. (Temp range low 46 - high 55)

3. Turned AC off - air on 68, fan 3, recirculating. (Temp range low 75 - high 77)

4. Second drive after car was in sun for 1 hour - air on 68, fan 3, recirculating. (Temp low 43 - high 55)


I’m guessing based on these results that the car does dial back the temperature of which the air comes out regardless if on Auto, after reaching target temp? But you can see now why I asked the question in the first place - because feeling the vent when it’s blowing at 43 feels like night and day compared to blowing between 55-72.

Sasnuke

I'm assuming the Second drive is the afternoon trip where you said it felt colder...what was the ambient temp then? I'm also assuming the 67 was the ambient temp in the morning only, and by the afternoon it was hotter out.
Even though I'm in Canada my house thermostat reads in Fahrenheit, and at 68 the family is complaining its freezing in the house...when it hits 71 the complaining stops.
For my car, right now it's set to Lo, which should be about 61F....so I don't need the AC on, however, I did turn it on today (in the afternoon) when it was 21C out (about 70F) still, because of the humidity (is was raining on and off today)...but the car ambient temp reading on the dash (for what it's accuracy is worth) still said 21C, like this morning, but the humidity this morning was nothing, so didn't even need AC then. I bet if I checked a weather network it would have said 21C, but "Feels like", followed by a higher number, because of the humidity.
The reason I leave it on Lo is because I don't need heat yet (we're now entering Fall), so basically I'm getting the air temp that's outside blowing through the vents.
Once you move off Lo, then you're getting outside air plus a small amount of heat from the car's HVAC system. The further you move from Lo the more heat is added
And yes the car won't run the AC constantly if it's not hot out because it doesn't want the Evaporator in the dash to freeze. It actually monitors the Evap temp as well.
And why I mention the humidity is because the AC really removes moisture from the cabin, which in turn, as the fan blows over the Evaporator, gives you the cooling effect you feel in the car...and why the excess water drips out the bottom.

I think I have a digital thermometer somewhere (for cars, not meat lol), so I'm curious what mine is doing.