Hi Guys
My front vents have started to blow only cold air when I have the setting on for heat, the rear vents still have hot air working, any ideas what is causing this
I have read online other Mercedes models with similar issues and they changed the HEATER COOLANT CONTROL VALVE, has anyone experienced this issue
Any info appreciated

Im trying to swap out the heater coolant valve located on drivers side underneath the windshield wiper arms, does anyone know how to remove the wiper arms, is there a special tool required or some trick, ive tried pulling them off with some force, they don't seem to budge
Any info appreciated

Well guys if anyone has a issue with cold air blowing out of the vents when setting is on heat it is most likely your heater coolant control valve, part cost me $80 Canadian from the dealership.
Its a pretty easy swap, took me about 1.5 hours, I had to take off the windshield wiper arms and there is a panel with 2 screws located underneath there to get access to the valve, it has 4 hoses attached to it and a electrical connector
It seems it is a common issue on Mercedes vehicles, a lot of W221 owners have had this issue and it is basically the same part they use for the W222 model, my car has only 80000 kms
Hope this helps anyone if they have this issue, the dealership wants 4 hours labour plus parts to do this job