I think it is a slow leak. It will not get cold. I went to dealer. Service wanted $100. to start. It will turn on and blow air.

There may be a fault in your Totally Integrated Power Module. Are the signals coming on and just staying steady? Are yourvparkkng lights working? Hazard warning? If so, I'd start looking at a defective turn signal switch.

first thing is to take it to an accredited ac service centre as you don't add fluid --only gas
it is added to the suction line of the compressor until the operating pressure is reached
by doing it yourself there is a distinct possibility that you will damage the compressor, over fill the system or do other costly damage
if you think you need extra gas then you have a gas leak which has to be repaired as a properly operating system will operate forever on the gas unless there is a mechanical failure or leak
fix the other problems first and then have the system checked.

Do you smell coolant inside of the vehicle. If so then chances are your heater core is going.

if the 100 is centigrade then if the coolant is full I'd replace the thermostat.

you can get a 134 freon fill kit with a fill hose on it and try to fill it yourself.
do you hear the compressor cycling on and off?if so thats a clear indication of not enough freon .
you say on the drivers side?
does it blow cold on the passenger side.?
if so this is an indication of the air handler not working right.
the freon fix will be easy but if theres an air handler problem its best to be left for the pros at the dealer that are use to working with and have heard of those problems before.
when it comes to mercedes unless you know exactly what your doing then dont mess with it.if you let anyone work on the car make sure its getting service from some whom knows what there talking about.if there is a leak the only way to be sure is with i freon sniffer tool.
no one i know rents them as they are very fragile tools.
also you may want to check any and all fuses.
as on these cars 90 percent of all problems on these cars are solved here.that car is way to new to have a freon leak.also check for any service recalls.
hope this helps
keep me posted
jm

sounds like it has a slow leak in it i would put dye in it and drive with it on for about 3 days and take a light see if u see dye comeing out anywhere

I suspect you have a very slow leak in the system. Get a can of freon that has a gauge on it. Connect ot he low side port on the a/c line under the hood and add a can of fren and see if the gauge reads OK. If low add freon. If good, take to dealer or a/c shop.
They can add dye to find leak with a leak detecter.

yes, after 9 years it needs to be recharged. Have a shop with a good reputation do it. Dont go cheap. It should hooked up to a machine so you can see how much leaked out,and test for leaks. shouldnt be more than $100

COOLANT TEMP SENSOR IS MOST LIKELY BAD. NEED TO CONNECT TO THE OBD CONNECTOR WITH A COMPUTER AND SEE WHAT TEMP THE COMPUTER IS SEEING.

I would assume with multiple people having the same problems, there should be a service bulletin on this issue. may want to call dealer with vin # to verify. sounds like a heater control issue under the dash. something i would leave to the experts for repair