Hi Tai - Please add your vehicle details to your profile so that it can be seen in any future posts..
I have no idea on the scenic but here's the laguna Method which MAY be similar..
OPERATION - FAULT FINDING
These vehicles are equipped with alternators with
internal ventilation and integral regulator. There is also
a warning light on the instrument panel which has the
***8211; the warning light illuminates when the ignition is
***8211; the light extinguishes when the engine starts,
***8211; if the warning light illuminates while the engine is
running it shows there is a "charging" fault.
LOOKING FOR FAULTS
The warning light does not illuminate when the
ignition is switched on.
***8211; that all electrical connections are good;
***8211; whether the bulb is blown (to find out, connect the
circuit to earth; the bulb should illuminate).
The warning light illuminates when the engine is
This indicates a charging fault which could be caused
***8211; the alternator drive belt being broken or the charging
wiring being cut,
***8211; damage inside the alternator (rotor, stator, diodes or
***8211; a regulator fault,
***8211; an overvoltage.
The customer complains of a charging fault but the
warning light is operating correctly.
If the regulated voltage is less than 13.5 V, check the
alternator. The fault could be caused by:
***8211; a diode which has been damaged,
***8211; a wire which has been cut,
***8211; charred or worn tracks.
Checking the voltage
Connect a voltmeter across the battery terminals and
read the battery voltage.
Start the engine and increase the engine speed until
the voltmeter needle registers a stable regulated
This voltage should be between 13.5 V and 14.8 V.
Switch on as many power consumers as possible; the
regulated voltage should be between 13.5 V and
Last edited by Laguna II Owner; 27th March 2006 at 01:59 PM.