Petronio

I have a 2007 GL 320 CDi whose A/C only cools on the passenger side. The driver side only blows warm or fresh air. The A/C controller on the dashboard has a blinking led light on the temperature knob. I have attached an image

Right temperature dial knob led light blinks
.
Compressor and thermostat are working fine. Gas has no leaks and pressure is ok.

The first diagnose said the A/C controller unit had a shortcut. I bought an used one and as soon as I installed it, the blinking light continued as it was before. What are the odds that both controllers have the same fault? Or maybe it shorted in installation and the problem is somewhere else? The computer diagnosed again a fault on the controller. Now I have to faulty A/C controllers.

The mechanic said the controller probably had faulty internal connections, so I had both opened, checked and resoldered. It did not work. Only the passenger side blows cool air, as it did before, driver side blows warm or fresh air.

Any help is greatly appreciated.

Max Blast

Do you often have a wet carpet on the passenger side footwell?

Miguk_Saram

Your Heater Control Valve may be defective, or locked in the closed position thereby not providing heat to the cabin. This was a common occurrence on the w211 E-Classe (rear vents would blow cold air when heat was on). Replacing the valve resolved the issue,

x164 heating system shutoff valve component description
w211 diy installing new changeover heater control valve

DennisG01

I had that exact same issue happening last summer. I did not have any codes, though, so what I'm mentioning may not actually be helpful (and I don't know why you would have that blinking light). But, I originally thought that the coolant oil and pressure was fine as I checked it myself - but it was just a cheap little guage. Anyways, my Indy checked it with their gauge and it turned out it was a little low. They added some oil and $5 later I had nice, cold air coming out the driver's side, again.

I'm not well versed in these areas, but maybe another thing to check into is "blend doors"? Or something like that - the thing that controls where the cool air goes based on temperature selection?

Petronio

Hi Max. Thanks for your comment.
No wet carpet.

Petronio

Hi Miguk. Thanks for your comment.

You got a point there. Let me check on it. Maybe it is open, it goes into the cabin and does not let the air cool, that is why right side cools and the left side does not.

Thanks.

Petronio

Hi Dennis. Thanks for your comment.

I will check on it, you have a point....maybe is a misdiagnose.