You might try to see if how it works for you.
I keep AC on in my car for 2 reasons
1. AC compressor need exercise from time to time and computer takes care about it.
2. quite often when driving in the humid weather with heat on, the windshield gets foggy. The MB clima takes care about it .. .if the AC is on. Driving Ford I am pretty annoyed that I have to make constant manual adjustments.
Correct, except that on a new car like a W211 the AC compressor runs always (no clutch), it is just turned to the minimum volume when AC is switched off (I think 3%). The compressor then gets exercised irrespectively of the ACoff button.
Originally Posted by sparkling_girl
I really trust MB engineering! But am just curious to see if i decided to use the heater manually and would not like to use any AC, ca i turn the AC off button? Is that the right way to use the heater?
I'm confused about your approach, what do you actually want to operate manually? You cannot operate heating manually, you can only set the preferred temperature and the car tries to reach that automatically even if you put "Auto" to off or ACoff to active (AC OFF).
You can switch HVAC fan speed to manual and you can switch air flow direction to manual but you cannot adjust heating power manually (that is: adjusting the air flow flaps between cold and heater air). Of course the AC compressor can also be switched off (functionally, not "physically" off), I think you are more after consequences from turning AC off.
If you wanted to, you could switch AC off at cold temperatures if cooling is not needed and if you face no problems with humidity (moisture condensing on glasses etc.). But you would not gain a lot because the compressor is not running at full power even at auto (although I think US cars are coded differently, Euro cars cool the intake air only sufficiently to keep relative humidity low enough while US cars at least used to have a coding that makes the car cool the air down to the maximum and then warm it up, but even here the difference is not significant if outside temperature is not high).