Air conditioning manual

Hello everyone:
I have a 1999 Peugeot 306 petrol and I'm having a lot of trouble with the air conditioning. My question is, do any of you have a manual for the air conditioning?
Thank you very much in advance.

What is your problem or exactly what do you need?

I'm not exactly sure what's wrong with it. I've taken it to an air conditioning technician several times, and he can't find the problem. He checked it with an infrared lamp and didn't detect any leaks. He thinks it's the gasket inside the compressor, but after paying him 120 euros to have it refilled twice, I don't trust him. I also took it to the same technician at the garage where I bought it several times, and he repaired some parts of the compressor. Now it's not working again. Tomorrow I'm taking it to another garage that specializes in air conditioning to have it tested again. I'd really like to have a repair manual for the compressor and other air conditioning sensors, since when I studied mechanics here in the Netherlands, they didn't give us anything about air conditioning [because it was practically nonexistent].
Regards.

If you used dye to detect the leak with the ultraviolet light and it didn't find anything, then the leak isn't there. In those models, it's common for the crankshaft seal of the compressor to leak. To detect it, you'll have to remove the compressor clutch; otherwise, you'll need X-ray vision. Another likely and common leak in that model is the evaporator. The quickest way to check it would be to shine the light through the evaporator drain.

As for compressor repair manuals, they're hard to find. On the other hand, repairing them or replacing any type of compressor gasket or seal is very simple for any average A/C technician. I say this because I do it for a living.
You said you refilled it with refrigerant twice. If I repair something, am I supposed to give you some kind of warranty or not?
Now in this market there are excellent, good, average, bad, and terrible electrical mechanics and A/C technicians. If you had a bad experience, try another one, but always ask what warranty the work has; that's what gives a shop credibility. Best of luck!

Well, first of all, thank you very much for your help. I took it to the air conditioning specialist and he finally found the problem. After doing all the tests, the first thing he did was inject hydrogen, but the pressure didn't drop in ten minutes. Then he tried the liquid to detect it with a test light, but that didn't work either; everything seemed fine. Finally, he injected the gas, and with the gas meter, he was able to find the fault, which was the condenser.
Well, the repair costs me a total of 374 euros, which isn't much, but I've thought about replacing the condenser myself. After all, it's just a gasket and oil, but I don't know where the oil goes. I think the condenser doesn't, right?
Best regards.