My 500SE has the dual temp wheel setup, and blows cold air from the dash vents whenever the AC is switched on. Last week I started getting intermittent blasts of hot air from the floor vents. Figured the “monovalve” might be having issues, so ordered two valve kits for the dual valve assembly. Found both diaphragms completely failed, installed new valves, now have temps varying from warm to melt your face depending on setting.
This is AZ, I either want cold AC or some heat for a few winter months, when my 300TD started acting similar to this I added a brass plumbing valve to the heater hose and shut the heat off completely from March to October. I may do similar here, but is there an issue I’m overlooking that causes this? In 90F heat like today, having a blast of hot air from the foot wells makes the car basically undrivable. Sometimes it does it, sometimes the air is cooled as the dash vents are.
This is AZ, I either want cold AC or some heat for a few winter months, when my 300TD started acting similar to this I added a brass plumbing valve to the heater hose and shut the heat off completely from March to October. I may do similar here, but is there an issue I’m overlooking that causes this? In 90F heat like today, having a blast of hot air from the foot wells makes the car basically undrivable. Sometimes it does it, sometimes the air is cooled as the dash vents are.
