EMR2004

Hi everyone,
My sisters car 04' E320 A/C quit working all of a sudden.

Here is my diagnosis:

Hooked up a diagnostics tool - got no codes from AC. only a few old stored codes that I erased and they didn't come back.

The FAN kicks on hard when I turn the A/C to max cool

The low pressue line shows that the pressure is high (when I connect a freon thing to it, it doesn't let me add anymore... ) because the compressor is not engaging. But at least it still has freon in the system.

I look at the compressor.. and it is turning OK.. How do I tell if its engaging or not? There is a tiny copper pin in the center of the compressor, that is not turning. Is that the indicator that it's engaged or not engaged?

I want to make sure that there are no other items that could have potentially gone wrong before I spend $300 on a new compressor and go through the hassle of taking the car to a shop to remove the freon and then re add it once the new compressor is back on.

Any potential electronics? or anything else that I need to look at?

Thanks!

kajtek1

Do proper troubleshooting. I posted link to procedure in 100 other threads, but you will find it at MercedesMedic.