Hello, I have 2012 E class saloon E220 diesel W212, when I switched on AC, passenger side blowing a bit warm air but the driver-side blowing cool air, but when it is a really hot day AC not very effective. What are the reasons for these issues? Thank you.

 

You'l need to scan for codes and look at live data (temp sensor values, among others) with appropriate scanner.

 

When is the last time the cabin filter was replaced? You know the one for the air you're breathing... when it's plugged up there's hardly any air that can circulate

When the air temperature is unbalanced from side to side, suspect the set of air actuators need service: either replace 'em -or simply clean and lube internals.

When the AC compressor short-cycles like every 5Secs... then it's another can of worms.

 

[cabin finger changed with the last service


QUOTE=CaliBenzDriver;8357000]When is the last time the cabin filter was replaced? You know the one for the air you're breathing... when it's plugged up there's hardly any air that can circulate

When the air temperature is unbalanced from side to side, suspect the set of air actuators need service: either replace 'em -or simply clean and lube internals.

When the AC compressor short-cycles like every 5Secs... then it's another can of worms.[/QUOTE]

 

Best to have someone pull codes preferably using MB diagnostics. As suggested could be faulty sensor, actuator however, may simply need refrigerant recharge inclusive of checking for leaks.