UPDATE
I have finally cured my charge light woes.
As per this thread the Battery charging lamp ( ECU feed ) shares it's connection Brown/yellow with the FBH temperature switch, located on a bracket behind the bumper.
This Brown /yellow exits the top of the switch, and joins a small loom, which in turn joins a grey multi plug sat behind the drivers headlamp, near the washer bottle.I have discovered a short length of this wire was corroded just above the switch itself, out of view and has been touching the body work, so shorting the 12v feed via the shared connection with the charge lamp, keeping the diode from receiving equal voltage to extinguish the lamp. !!
In the meantime all the alternators I have fitted have charged the battery with no problem.Her kitchen looks like a scap yard
So quite pleased after spending on unneeded items.
PS
This fault could also effect the operation of the FBH ,as a reduced or incomplete connection would effect the voltage to trigger pin 1 on the FBH six pin plug to start it at the appropriate temperature. It is known the FBH is sensitive to voltage variations.
Anyone with a charge light problem on a diesel, even if all the components have been replaced should have a look in this area, similarly anyone with FBH start up problems, on the basic factory set up that depends on temp switch to start the FBH.
This maybe of use to some one contemplating swapping a voltage regulator over :-
Label differences in the two types of DIESEL alternators I know of
EARLY TYPE 115 AMP YLE102500
If you need to replace the voltage regulator for this type see here :-
http://www.ebay.ie/itm/VERG1019-VALE...item46122e061c
LATER TYPE 120 AMP YLE000260
If you need a voltage regulator for this type see here :-
http://www.ebay.ie/itm/ALTERNATOR-RE...item257ccd668a
I spoke to the guy selling the voltage regulators of the first older type 115amp and he has told me that it is regulated at 14.2v and only the two pin outs required for the diesels are connected internally. 15, 61e. even though there may be three pins in the regulator plug socket.
Beware the fitment on these voltage regulators, the 120amp version will not fit the 115, nor vice versa confirm your type visually if possible, before ordering.
Snagger.