pedrobenz

Thanks popey24. I figured it's the Evap temp sensor so I ordered one today. I will pick it up tomorrow and will install it tomorrow as well. Will let you know if it worked.

pedrobenz

I replaced the Evap temp sensor and still having issues. I took it to a local a/c shop and they said it's the expansion valve and the drier that I need to replace. Will the compressor not kick in if the expansion valve or the drier is bad?

popey24

Is your compressor running or not? If yes, please measure and post the Parameters before starting the a/c, after starting a/c and 5 minutes later.

The dryer is exchanged only when the System gets opened, f.e. when you Exchange the condenser or the compressor.

The Expansion valve is a thermical one, there is not much that could be damaged.

pedrobenz

Thanks popey24. The compressor sometimes work and sometimes doesn't.

In the morning when it is cold, when I turn on the A/C, the compressor will not turn on.
The readings this morning were:
01-68
02-63
03-58
05-60
07-LO
08-68

When the temperature outside went to 80F, the compressor turned on.

I noticed that in the morning when it is cold, the compressor will turn on only when the engine reached its normal temperature and will turn on the auxiliary / condenser fans. The compressor also works when the weather outside is above 75F. Why is that? Am I low on refrigerant? Or is it a bad refrigerant pressure switch?

popey24

Your condensing pressure probe is broken or your System is empty.
With System mot running, the condensing temperature is almost outside temp (08: 68°F=20°C). The corresponding pressure with R134A should be 5.7bar (you need to convert to psi or what you are using), but it is LOW.
Maybe the condensor is damaged, maybe the probe. But Forget that fool that told you your valve is damaged.
Anyway you should Exchange the dryer, because you Need to open the System in both cases. The condensing press probe is lokated on the dryer. behind the Driver side headlight.
I am not shure, if the probe shows LOW or 0.0 when System is empty. I believe there is a threshold below it shows LOW to Show system is empty (leakage). Probably 90% or more it is the condenser.
If you have contrast fluid inside your System, you can detect the leakage with UV light.

pedrobenz

The system is not empty. It could be the refrigerant temp sensor or the refrigerant pressure switch. There is refrigerant in the system. Maybe not enough. I will check again. Thanks again and will let you know.

Sulaco

The system is most likely not low or empty. Your compressor working intermittently indicates there is pressure present to be intermittently detected and thus making the compressor engage. Still a huge likelihood it's a sensor (pressure, evap temp)

popey24

For sure that's your Problem: 07-LO
normally press probe broken or leakage.
If it is fine sometimes, maybe you have a contact Problem (corrosion)?
There is an outside temp Limit that blocks cooling, but is is rather low (I think 4°C / 40°F)

pedrobenz

Hi popey24. I called my local MB dealer and asked for the pressure switch. They have it in stock so I bought it. I took it to the same place and asked then to recover the freon and replace the pressure switch. He replaced the pressure switch, evacuated the system, and charged with R134a - 1.9lbs. In started the car and turned on the A/C and viola! The A/C worked!!! So it was the pressure switch after all. Thanks for your help.

savage6br

I followed the directions and got the EC light to turn off. Ya. Now lets hope it stays off. Jeff