Item description
EC button: economy mode when the light is on (amber), means AC OFF
REST button: The REST button in a Mercedes keeps the cabin warm for up to half an hour after the engine has been switched off. A small fan blows warm residual air from the engine bay and coolant system into the car interior to help keep you warm even when the engine isn’t running.
EC button always turns on by itself when key turnsy and doesnt wanna go off not unless key turns off and on again. What's the problem?
Start the car, but do not touch the gas. Let it idle in park. Turn on the AC. Press and hold the "REST" button on the climate control. After approximately 5 seconds, the display on the climate control will change. After the display changes, you can let go of the REST button. What have just done is put the AC in diagnostics mode. On the climate control display, you will see 1 on the left, and another number on the right. Write down both numbers. Press the AUTO button on the left side. That will cause the number on the left in the display to change to 2, with a different number on the right. Write down both numbers again. Continue to do this until you have numbers 1 through 8 (on the left) and the corresponding numbers on the right side of the display written down. You can press the REST button again after you have written the numbers down. Pressing the REST button again will take the AC out of diagnostics mode. Post the numbers you wrote down here, and I’ll take a stab at telling you why the AC isn’t working.