Mondial T low idle engine stall with AC

Hello,
I own a 1991 Mondial T, F119DL000 engine, Motronic 2.5 without catalyst. After putting the air conditioning back into service, I have a problem with low idle engine and stall when the ac compressor is engaged. I tested the accelerated idle on the steering system, it works well when the hydraulic pressure is above 30 bar. I tested the information that comes pin 40 of the UCE, I have well the 12 volts when the clutch is powered. I would like to know if the two idle systems act on the same circuit of the 2 solenoid valves bypass and which is the "pin" that controls its solenoids. I do not have the information in the manufacturer’s documentation. Thanks