SFML320

even when the temp setting is at the lowest, there seems to be warm air blowing in, when the outside temp is hovering around 63-65F.

of course if i turn on the a/c, then cold air will blow in. but i shouldn't have to use a/c when the outside temp is colder. is there anyway the dealer can calibrate the temp setting?

i also feel like there is hot air coming into the cabin, not sure if it's from the firewall or underbody. will have to crawl around one day when the engine is running.

1FSTAMG

Not sure if it helps, but when I turn off the A/C via the button, the air coming in the vents gradually changes to be close to or the same as the temperature outside.

Not sure when the air coming in would be warm when the outside air is cold. Check and see if it does the same thing when first starting the car. This would eliminate engine heat from causing the warm air. If the engine is cold, the outside air is cold, and the air coming in from the vents is warm.....probably something wrong.

sdsilverm3

I think it's normal. This isn't the first thread where people have complained about the "stale" air.

MercedesFTW

Yea I thought I read that only fresh air is blown in when you use A/C?

spr

I have *****ed about this forever to my very close master mechanic/ shop foreman at the dealership. The deal is that the control doors don't just change instantaneously they do it very gradually, hence why any and all changes do not appear to do much of anything, although they do after a couple of minutes. They can also sync the doors and I noticed this helps a tad, but the entire system is rubbish. He even stated "I don't know why they even put numbers on the knobs"

Another thing to make sure of is that the filter and intake cover is property installed, it's very common for it not to be seated properly which will allow hot underhood air in. I also have an activated charcoal filter which makes a world of difference.

SFML320

thanks spr, i'm going to check this weekend. anyone have pictures of the intake cover?

spr

I don't but if you look there are tabs on the bottom of the cover that must be inserted to make a proper seal-It's tricky with the flip locks on top

1FSTAMG

I did a little test today. Driving down the highway I pushed the A/C off button. The air blowing in stayed cold for 7 full minutes! Then, after 7 minutes it FINALLY switched the A/C compressor off and the air changed to outside temperature (102 degrees!) instead of the 70 degrees I had it set on with the A/C on.

I wish I knew why it takes so dang long for the system to respond.

I'd like to be able to turn the A/C off and run fresh outside air through the system to "dry" it out before parking for the day at work or evening at home.

rbaker

If you want the "AC OFF" to actually shut the compressor down quickly (less than several minutes), you'll need to manually disable the "AUTO" mode & actually shut the fan off for a few seconds. Then you can turn the fan back on & the AC compressor will be off.

SFML320

Update: Dealer deemed the ACC unit, which is the entire control panel, faulty and replaced it. One obvious difference is that the "AC" button is now reverse, light on means AC is ON compared to having "AC off" on the button.