85 300TD a/c compressor won't work

I recently converted my a/c on my 85 300TD to R134. The system had a huge leak in the suction hose, which was replaced. The system was evacuated and I added three 11-ounce cans of refrigerant, but the compressor will not turn on. It was working fine before, so I was wondering if there was a switch or something that is not functioning properly, or if more R134 needs to be added.

Forums

Body and Interior Specific Aid

Chassis Model Number

W123

proper pressure

Hi Quaybon. I have been looking at your post as I try to learn from other people's problems and that is what makes this site a wealth of knowledge. I would guess that you would rather hear from the experts and so would I as I am not an expert. That said I will give what I have to offer and hope I am close to being right. I have been told there is a pressure switch in the system that will not allow the compressor to come on, so as to protect it, unless there is a proper amount of refrigerant and thus the proper pressure in the system. If you know anyone that does ac work, not only in cars but any application, ask them to corroborate this. Anyone that does ac work has a set of gauges that aids them in achieving that proper pressure. Where that switch is located on your car, I don't know.