Lada Niva Motor Lighting Failure.

My question, if someone can guide me, has a failure when the volimeter passes the 13 vlts, begins to kick, but if I turn on the long lights, when lowering the load of the alternator, it normalizes, and I do not know whether to point to the module, to the coil, or to the captor, and I would not want to change any of these without being safe, the engine starts perfect and with the light light You know about the subject, it will be appreciated, my email is. thank you so much.

Before changing anything, you do well to make sure, I will tell you a similar case in a Renault Megan I, when stepping on the brake or lighting lights I stopped rating, the problem was the free pulley of the alternator was damaged and raised until you made the alternator work, it changed this and "hand of saint", I do not know if the niva carries this type of pulley in the alternator. You can also check that the alternator regulator is well.