nsve

Well, everything solved. Problem was in the new sensor which is said to be compatible and is not OEM - sensor KTT130000. On osciloscope its showing good voltage out readings and pwm shape, when it is connected on longer wire it drops down, its signal power is probably less than on original sensor, and due to not perfect resistance on climatronic input, it drops down. When sensor connected in cabin, on 20cm wire, powered from 12V lighter there is no fault any more. In the end I used NE555 timer chip tuned on 50Hz and 70% PWM and AC is working, ofcourse this is dangerous if you dont know what are the pressures in the system, this is until i buy new sensor. I hope this helps someone.

Well, after five years, maybe some of you have explanation for this problem. I have same problem, AC not working, removed old sensor, inspected it - it was full of oil and chip on the sensor was burned, that was also the cause of losing refrigerant over the years. I bought new sensor from Aliexpress (99% things I bought from there was functional), after that I checked with VCDS and got same G65 pressure sensor short to ground, after that i started to have suspicions about that chinese sensor and bought new one in big european spare parts shop, the outcome is the same. Next thing I did was buying new climatronic(used but like new, instead of old and worn) because I was thinking that maybe the input on pcb was dead because of burned sensor. I have measured all the lines, sensor is powered with 12V, even I did direct connections from sensor in my hand to the climatronic unit with new wires but still everything is the same. It is started to be frustrating and I dont have a clue yet.

I want to say hello to everybody in this community, lots of nice and helpful posts are here. I am from Croatia, driving Octavia from 2007. My interests are mainly in electronics.