Air conditioning in Peugeot

We are several owners of a Peugeot 306 and 405 with the same problem, Jo's air conditioning when the account revolutions stopped approaching, by discard we understand that they have to be united somewhere.
The paintings work well in other cars in which the emos tested by what they are not. The problem is in a revolution or PMS account collector but in no manual, where it is and how to adjust or change it if they knew where it is and how to fix it we would appreciate it very much.
Thanks beforehand

Hello, the problem is in the alternators, the reading of the RPM makes them at the W about the alternator, the most caused thing is that when the alternators are not properly locked, the AA is blocked.
I hope this information is useful.
Greetings.

The PMS collector is at the rear of the gearbox, between the union of the box with the engine, between the cylinder butt and the output arrow of the differential side differential. This collector is generating type if you disconnect it and check the voltage reading between terminals 1 and 2 must give you 4V to 9V, terminal 3 is shielding to avoid parasitic noise to the signal that goes to ECU but this is put to negative mass or earth, does the engine go out or only the rpm shown fall?