well the problem is that on the passenger side the a/c i s working ,but on the driver side is not cooling properlly . I was told that it could be the thermal water valve but I will like to comfirm that info please help. thanks in advance!!!!!!!

 

By "thermal water valve", do you mean the thermostat? If that's what you mean, that is not the problem. A thermostat at the front of your engine regulates the flow of water through the radiator, keeping the engine temp. at the proper temperature. If the thermostat is working properly, it wouldn't have anything to do with the a/c temp. Heat, yes. A/C, no.
If the A/C is working on one side and not on the other, chances are it is something going on under the dash where this is regulated. If only one side is cold, the problem is not under the hood.

 

I had the same problem it is the solenoid valves that control the heater valvs they are located nereby the airfilter box but more to the back side the piston jams inside them and gets stuck on the heater position i had my heater by passed because i live in sa dont need heaters hehe if you have any questions please feel free to email me @ markvanrooyen01@gmail.com

 

i just got my c230k merc and i have the exact same problem. cold on the right and neutral on the left. my heat works fine and im sure if urs does too than the last post was wrong to diagnose our problem. i think he was just talking about heat but im not sure, so if some more info were available id really appreciate it. thanks

 

before you start throwing parts at your car...make sure you are not low on refrigerant. this could cause the same complaint.