On my 190 e 2.3 1987 benz there are are 3 buttons on the right hand side of the climate control console.
For a while now i have eeen having issues with getting cold air from my a/c. Infact i've had the compressor &, dryer replaced.
My problem is the when i get the sytem charged it usually puts out cold air while its being charged,when i hit the a/c button.
On hot days the a/c button wont work,hot air ends up coming from the vents. Inorder for me to get cold air from the a/c i have to hit the defroster button just above the a/c button.
My question is why does that occur? Is there a faulty connection on the a/c button?
What other things can i do to diagonois the sytem?
Does the defrost button automatically engage the compress, thought that was the purpose of the a/c button.

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