How to test the alternator of the Lancia Phedra

Let's see how to test the alternator of the Lancia Phedra with a multimeter: the test is performed without removing the alternator from the car: it is isolated by disconnecting it from the wiring, and its internal components are tested one by one. Before starting, let's disconnect the negative terminal of the battery. Then, we remove the 13 mm nut from the rear terminal of the alternator, unplug the clip electrical connector, and remove the voltage regulator. Now the alternator is ready for testing.

We start with the rotor test: we test the internal coil of the rotor. Set the multimeter to Ohms and place the probes on the two collector rings. The expected result is a resistance between 2 and 3 Ohms. If the reading is infinite or 0 Ohms, then the rotor is faulty. Now we proceed to the rotor insulation test (that is, whether the rotor winding is grounded). Leave one probe on a collector ring and place the other on the metal casing. The reading should be infinite: if it shows a low resistance, the rotor is grounded (and therefore faulty).

The rectifier bridge test allows us to check the 6 diodes that convert alternating current to direct current. We test them for short circuits and open circuits. Set the multimeter to "diode test" and place the black probe on the main terminal, while using the red probe to touch each of the output terminals of the stator winding in turn; then we reverse the probes. In one direction, we should have a reading of 0.4/0.5, while in the other direction it should be infinite.

The stator-to-ground test is performed by setting the multimeter to the continuity mode. Place one probe on any of the three copper terminals of the stator and the other on the metal casing. The expected result is no beep and an infinite reading; otherwise, the stator is grounded (and therefore faulty).