Megane II vehicles are equipped with internally ventilated alternators with built-in voltage regulator and warning light that comes on and off when the ignition is turned on:
If the warning light comes on while the engine is running, it means there is a “charging circuit” fault
The stator 5 (fig. 1) and covers 2 and 6 are tightened with four bolts 3.
The rotor shaft rotates in bearings that are installed in covers 2 and 6.
Power to the rotor winding (field winding) is supplied through brushes and slip rings.
The three-phase alternating current induced in the stator winding is converted into direct current by a rectifier unit attached to the back cover 2.
The voltage to excite the generator when the ignition is turned on is supplied to the output of the voltage regulator.
The operation of the generator is monitored by a battery discharge indicator located in the instrument cluster.
When the ignition is turned on, the indicator should be on, after starting the engine it should go out if the generator is working.
The bright burning of the signaling device or its glow half-heartedly indicates malfunctions.
The accessory drive belt is tensioned by an automatic tensioner.
Possible generator malfunctions and solutions
Fault Remedy
When the ignition is turned on, the battery discharge indicator does not light
Wire break between alternator, ignition switch (lock) and bulb - Repair break
The low battery indicator does not go out after starting the engine
Low tension on the alternator drive belt - Check and tension the belt
Faulty alternator - Replace or repair alternator
Short to ground wire between generator and signaling device - Insulate the wire
The generator does not provide battery charge
Oxidation of battery terminals - Clean, secure and lubricate battery terminals and tips
Battery defective - Replace battery
Loose alternator drive belt - Check and replace the belt
Generator voltage regulator or rectifier unit defective - Replace voltage regulator or rectifier unit
The battery is being recharged (begins to boil)
Generator voltage regulator or rectifier unit defective - Replace voltage regulator or rectifier unit
Increased voltage drop in the generator-battery circuit - Check, clean, tighten or replace the contact connections in the ignition switch, fuse and relay mounting blocks, connectors, check the connection of the generator housing to ground.
Removing and installing the generator
Disconnect the negative battery terminal
Press the wire block retainer
Disconnecting the wire block
Unscrew the nut that secures the end of the wire with red insulation
Remove the wire end from the generator stud
Remove the alternator drive belt - Replacing the accessory belt for Renault Megane 2
Unscrew and remove the bolt securing the bracket to the generator
Unscrew the nut that secures the bracket to the cylinder block
Remove bracket
We unscrew the upper bolt of the generator.
We also unscrew the lower generator mounting bolt
We extend the bolt to the distance "A" (the bolt is removed in the picture)
Remove the generator
Install the generator in reverse order.
Tighten the alternator mounting bolts to the required torque (25 Nm)