ClasseMiaMadra

Sunday - Someone in my household was fiddling with the light switch of our 2012 S550 4M while she was driving.
Monday AM - she calls me to say that the she was alerted by a neighbor that the rear lights were on all day and ask me why? My response: is it one side or both? even though I was not sure why the fog light will remain on even with the ignition switch off and the key away from the car (it is clipped inside her purse. Answer is "both" so I am thinking that it is likely sunlight reelection, and if not, the LEDs will likely not kill the battery overnight, or even the car may shut it all off.
Monday PM - She calls me to tell me that the battery is dead. Triple A solves this and all is well.
Wednesday AM - she calls me to say that the AC is not blowing cold air any more.

Question 1. can the drained battery affect refrigerant level? sounds kind of dumb as a standalone question but under the S Class context... I dont know, but I am not sure...
Question 2. can the car's AC be filled the normal, regular way with off the shelf refrigerant at any repair shop ?

Thanks.

ygmn

1 - no
2 - why?

Your AC Worked before battery change/charge... should work after unless one of the many computers on the car did not reset properly and there is soem funky MB procedure to reset the AC system after battery change

ClasseMiaMadra

You are correct in your summary. and since the car is not nearby to take it to my mechanic, I dont want to risk taking it to some random upstate shop for anything to involved. Maybe I can find someone to check the refrigerant level. If it shows good pressure, then maybe look for any codes and we go from there. I did confirm in the meantime that the refrigerant is the standard R134a so that should be easily available. .

Any local recommendations for Lake George /Saratoga /Albany area in upstate NY ?

DrDoe

Refrigerant level somehow dropped off is very unlikely. You should try to look for an AC reset procedure. Look at the AC buttons to see if there's any red indicator light.

ClasseMiaMadra

Looks like you may be right. The AC apparently blows cold air still, but only when on LO temp setting. a single degree up will turn it to warm. If anyone has seen a thread they remember, or keywords, please share.
Thanks in advance.

DrDoe

If that's the case then the temperature sensor went bad. Search W220 AC temperature sensor issue for a fix.

DrDoe

I would try the W220 AC reset procedures first to see if it makes any differences before looking at the temperature sensor.

ClasseMiaMadra

Thank you guys. Just curious though, why W220 ? just a typo or are they the same ?

DrDoe

Hi. I searched but didn't see anything on W221 that's why I mentioned W220. My W220 AC was fixed for both issues. Yours W221 problem would be something along the AC reset and temperature sensor. Somehow your story is similar to the story of my daughter calls.

ClasseMiaMadra

Yes, I was also surprised to not find anything on resetting the W221 AC. Let's see. I will be plugging the code reader tomorrow and see if there is any code there.

BOTUS

I disagree, as the car ages an increasing level of refrigerant gas will leak out… around 7 to 9 years the condenser fails and the leak gets significant... over the next year if not topped up it will stop on low pressure.

what usually happens it either routine maint or as AC not as effective, it gets topped up enough to last another season even with a small condenser leak... by this age usually some one just keeps topping it up each year and then the car is thrown away for other reasons at 10 to 12 years and thus many owners don't realise there was a small leak for many years

BOTUS

the simple test.... for a condenser leak
open the bonnet and look at the "rad at the front" this is the AC condenser... look round the sides top to bottom, looking for dark dusty possibly oily patches, rather than nice clean aluminium... if you find a dark dusty patch the condenser is leaking