Does not jump the compressor (Citroen C3)

Hello, I am trying to locate a failure in the air conditioning of my car, the fan works but the typical noise of when the compressor jumps is not heard, apart from the fact that the air does not come cold, I have disconnected the connector that goes to the compressor and I have put a polyimeter in direct current to measure the voltage that reaches it, when I start the air conditioning the voltage rises almost to 14 V, but the problem is that the problem is. And it goes down to 11; 30 V, according to I have verified in another car the voltage does not have to oscillate, since in the other car I gave me 14:40 V and this does not oscillate, I think it can be an electrical problem, I do not know where to start, I would appreciate the help of someone who was put on this.
thank you.

Still after a few weeks I still turn around the air conditioning, I was looking at what the partner Ismael53 told me even if I did not try the compressor coil because I did not see how to access it, what occurred to me was to ask for an obd scanner and connect it to the BSI and gave me the p0532 code It will be to go to a workshop and say that they load my air, I hope it is a lack of gas, and as a consequence, this week I tell you how it went.

Hi Trohn, one of the causes for which the compressor (the "clac" that you say should be heard) is not clutch) is due to lack of gas (some leak), the prisoner detects that there is no pressure and then does not let the compressor in that not flu this (it is greased by an oil that carries the gas), another different problem that it can have is that the magnetic coil This cut (does not act from Electroman) proves its resistance in case ... A advice is that during winter, it is very good to put the AA running from time to time about 15 min. to lubricate the entire circuit. Another problem that can be is a defect in the bulb or room temperature sensor (it acts like a thermostat), but this failure is already more remote. Well, you can check the coil with a direct positive (to see if it clutches), the following is to check the gas load. Greetings!!

Hello, I continue with the theme of the air, as I said in my last edition of the message, take the car to load the air and they told me that there was an electrical failure, I continue to spin and ask me because when the action the ac is low prisoner? or the room temperature sensor? If that were the case as I check these components, the prisoner has 3 cables, to see if someone throws me a hand.
THANK YOU