fumiyasu

First time in a while that the sun is out in the UK, thought I would turn on the AC but it just blinked a few times.

According to the manual, that means there's a fault somewhere, but does anyone know if it means anything more specific? As in, could it range from out of refrigerant to sensors etc. or does it point right to the compressor not engaging?

Just wondering if I should try a re-charge first or if I should get it diagnosed at the dealer when I get my service this month?

Glyn M Ruck

It is probably low refrigerant. There is a pressure/temp sensor at the front condenser to protect the compressor. You can't diagnose anything on the system without correct refrigerant pressure first. Have it topped up/checked for leaks.

fumiyasu

Thanks, exactly what I wanted to know..(or hear I guess)

Big Daddy

if you do not run your AC regularly the seals will dry out and leak. Best to run your AC for a minute or two every couple of weeks during the winter to stop this happening

RavenMDX

Found out last week car has 2% refrigerant left. Essentially hot air was coming out. Hoses were vacummed and topped up and checked for leaks. Been fine since.

fumiyasu

Yea, I sort of knew about the AC always on thing but I just got this car a couple of weeks ago. Think the previous owner was more concerned abt gas mileage than anything... Hopefully the dealer will sort it out for me without expense...

Raven, I guess the AC button didn't blink on you then?

Sportstick

You're going in the right direction, but I will take it a step further. Put the system in AUTO, leave it there, and adjust the temp dials to suit you. The system takes quite good care of itself in AUTO, runs the compressor as needed, and is generally smarter about it than the driver, unless an extreme requires MAX COOL or concentrated defrosting action.

RavenMDX

I picked up the car this winter so I never bothered to check the AC even though it had just gone through a PPI at the local benz dealer. Obviously they didn't check everything...figures.

I assume that the previous owner didn't use AC..

OvOMitch

Sorry to revive this thread, but my AC button started flashing this morning when I tried turning it on. I run the AC pretty much everyday. Would it most likely be low in refrigerant? What are the chances of it developing a leak if I run it regularly?

OvOMitch

I should also mention the weather here is pretty cold along with freezing rain. Would this trigger the AC not to run? I like to run it because I find it helps in de-fogging the windows. Although I do not recall having this problem last year when the weather got this cold.

OvOMitch

UPDATE:

On the drive home, I pressed the AC button again just to see if it would work and VOILA! It turned on without the flashing red light. What do I do now? Everything good or do I still need to get it looked at?

This morning was the coldest weather we've had this season thus far. It wasn't as cold/wet when I got out of work and turned the car back on. Could the adverse weather have tripped a sensor? Really trying to avoid a trip to the dealer. They want $120 just to look at it.

ques0059

Hi, i am finally a Benz owner, I noticed yesterday my A/C light was flashing when I tried to turn it on. Has anyone figured out the problem?

Thank you,
Tony

OvOMitch

I don't have any updates other than it has been working fine since the incident I wrote about above. Has it been unusually cold where you are located? I have read on other parts of the Internet that a drop in temps can cause a drop in pressure in the AC system, basically making the system think it doesn't have enough refrigerant to run. It's basically protecting itself when it refuses to turn on. Check your refrigerant levels first. Add more if needed.

Alex.currie44

This is an old post but I just ran into the same issue with my 2013 C63 AMG. Leaking condensor/evaporator. When you inspect it with glasses and UV light it glows the colour of money!!
There was some comment re the AC being on all the time even when you shut it off on the dash. This is true. The system runs to dehumidify the air blowing on the windshield to reduce and prevent fogging inside.
Age will attack seals too not lack of use because it is not a case of not being used. It is always on but actually under less load.