Intermittent AC Cooling Issue on 2006 Mercedes Benz B200 W245

Hello
Thank you for having me here.
Join up as I have problems with A/C on my 2006 Mercedes Benz B200 W245.

A/C gets cold intermittently approx. 1 out of 10 times of use.
Problem is with the car since I have it.

I am a truck mechanic at Volvo so I have A/C experience.

Last year replaced the compressor as it was noisy and the condenser looked like maybe damaged.
Evacuated the gas and vacuum leakage all fine, regassed all ok. 0.8kg.
Still only working intermittently...
Later in the year after winter replaced the expansion valve, evacuated, checked for blockage in all pipes, vacuum test ok and recharge, still intermittently getting cold.
Replaced the in-car HVAC controller (second hand, and cleaned the sensor of dirt with electrical cleaner) thinking maybe interior sensor problems
Still intermittently not getting cold.
Measured voltage at sun sensor 5v.
Resistance of sun sensor approx 12kohm at 21c.
Pulled fuses swapped no help,
When A/C working is really good cold temperatures.

What can be wrong?
Thinking run wire straight to A/C compressor plug but not sure if voltage?

Thank you

AI: Can you provide the ambient temperature conditions when the A/C fails to cool properly?
10 to 25 degrees
AI: Have you checked for any error codes or diagnostic messages from the vehicle's system that might indicate an issue with the A/C?
Yes no fault

When it does not work, suspect the parameters.

Dziękuję za odpowiedź. Nie rozumiem Cię, co masz na myśli mówiąc „podejrzewam parametry”?>>21481769

And tell me where I wrote that I suspect the parameters? 😂😂😂

Ireneo wrote:

When it does not work, suspect the parameters.

Perhaps we are getting confused with each other with our possible different languages 😄

I'm not understanding what you mean by your reply in regard to parameters?

Thank you

The operating parameters of the air conditioning system can be read out with a diagnoscope, e.g. what is the HP pressure in the system when the air conditioning system is cooling and when there is a fault. The same with the valve control signal on the compressor

I see the translator has translated you badly. You have the answer above. Diagnostoscope parameters when the air conditioning is not working. You may find something that causes the malfunction.

pressures are as expected for the system, I remember when I regassed it was looking normal.

yesterday A/C would not work for about 20 mins of driving then worked perfect for approx. 30 min then went warm again

Today I have checked voltage going to the compressor at the connector and it shows 8.64v approx.?

I have made a direct switched fuse able power jump wire to test when the compressor has full battery voltage, and it still didn't work-
But I think the reason for that is the voltage supplied to the compressor is probably PWM power, so stable voltage won't make it work effectively?

Any other ideas I can try?

Added after 3 [hours] 57 [minutes]:

with this power jump cable connected, A/C worked after a long time and then it stopped working , ... so it is still the same?