You will need: 13mm and 15mm socket heads, flat-head and Phillips-head screwdrivers, and an ohmmeter (autotester).
1. Remove the generator from the vehicle (see "Removing and installing the generator").
2. Remove the screw securing the back cover.
3. Unscrew the two nuts...
4. ...and remove the rear cover of the generator.
5. Remove the three mounting screws...
6. ...and remove the voltage regulator.
7. Check the ease of movement of the brushes in the brush holder and their protrusion. If the brushes protrude from the brush holder by less than 5 mm, replace the voltage regulator assembly with the brush holder.
8. Check the rotor winding resistance with an ohmmeter (tester) by connecting it to the contact rings. If the ohmmeter shows infinity, then there is a break in the windings and the rotor needs to be replaced.
9. Check the rectifier block diodes. Connect one wire to the rectifier block ground, the other to the diode terminal...
(Original of this article on the website: RenaultBook)
10. ...and then swap the wires. The diode should only allow current to flow in one direction. If the diode allows current to flow in both directions, it is faulty.
11. Check the remaining diodes in the same way.
12. To replace the rectifier unit, use a screwdriver to loosen the twelve contacts...
13. ...unscrew the two mounting screws and remove the rectifier unit.
14. Assemble the generator in the reverse order of disassembly.