Did my air conditioner clutch come undone? According to the 2014 Standards
Posted: Tue Jun 30, 2026
The air conditioner in my car is acting "as designed" or maybe the clutch is "sticking" and refusing to let go of the compressor, so I can't figure out how to turn it off.
It is a 2014 C180 S204 (a German car) with the license plate OM651.
A few specifics:
The air conditioner is flawless; the speed of the cabin fan increases automatically upon activation and decreases upon deactivation, and the light on the AC button illuminates properly. All of the HVAC controls are turned off or set to manual, and the temperature is completely cold on both sides.
Issue at hand:
The air conditioner continues to blow extremely cold air for several minutes after I turn it off, regardless of how briefly it was on.
I conducted this empirical test yesterday:
After 20 minutes of driving with the air conditioning on "front and feet" and the fan set to maximum speed, the car's temperature had stabilised.
With the outside temperature at 36°C, I was travelling at a speed of approximately 80 km/h, or around 1500 rpm.
In order to catch the blast from the left side vent, I had my left hand open and resting on the steering wheel. As soon as the air was no longer cold, I turned on the air conditioner. After approximately 5 seconds, the air temperature dropped again, so I turned the air conditioner off again while keeping the fan speed set to maximum. The fan speed slowed down slightly after turning off the air conditioner, but that was par for the course.
The air emitted was chilly for the first seven minutes, but it warmed up fast after that.
This begs the question:
It appears like the compressor was running the entire time the cold air was being expelled. Is this the intended behaviour or am I totally mistaken and the evaporator can be cooled down to the point where it takes seven minutes to heat up again after just five seconds of running?
It is a 2014 C180 S204 (a German car) with the license plate OM651.
A few specifics:
The air conditioner is flawless; the speed of the cabin fan increases automatically upon activation and decreases upon deactivation, and the light on the AC button illuminates properly. All of the HVAC controls are turned off or set to manual, and the temperature is completely cold on both sides.
Issue at hand:
The air conditioner continues to blow extremely cold air for several minutes after I turn it off, regardless of how briefly it was on.
I conducted this empirical test yesterday:
After 20 minutes of driving with the air conditioning on "front and feet" and the fan set to maximum speed, the car's temperature had stabilised.
With the outside temperature at 36°C, I was travelling at a speed of approximately 80 km/h, or around 1500 rpm.
In order to catch the blast from the left side vent, I had my left hand open and resting on the steering wheel. As soon as the air was no longer cold, I turned on the air conditioner. After approximately 5 seconds, the air temperature dropped again, so I turned the air conditioner off again while keeping the fan speed set to maximum. The fan speed slowed down slightly after turning off the air conditioner, but that was par for the course.
The air emitted was chilly for the first seven minutes, but it warmed up fast after that.
This begs the question:
It appears like the compressor was running the entire time the cold air was being expelled. Is this the intended behaviour or am I totally mistaken and the evaporator can be cooled down to the point where it takes seven minutes to heat up again after just five seconds of running?