Detect FAULTS IN THE ELECTRIC FAN with a multimeter

The radiator fan relays can fail due to damage to the relays, relay wiring and the car's computer.
With the help of a multimeter we can measure the voltages of the relay sockets and know if the computer is delivering the correct voltage values.
When we measure the voltages of the socket of a relay in good condition we must have the following:
Terminal 86 has a voltage of 12 volts (battery) and terminal 85 a voltage of 3 volts (control from the car's computer).
If these voltages are not present as indicated in the previous lines then there is a problem with the wiring or the car's computer.