Alternator/Wiring issue 52plate combo van???

About 6 months ago i bought a 52plate combo van, when i bought it, it had just had a new alternator fitted..

For a past few weeks now, the battery light has been coming on and off, the lights have been dimming etc..

then on saturday i went to work on my nova sport, came out of garage and got into van and the van turned over but didnt fire.. the battery went flat.

I automaticly thought it would be alternator, put a brand new alternator on and it wouldnt charge. Light still on!

Put a new battery in it, no different again.

Now, the alternator that is fitted to the van has a big main connector for the power and it has a 2 pin plug aswell..

On my wiring loom there is no 2 pin plug, just a single blue/white (iirc) with a spade terminal on the end. This was plugged into the top one of two terminals on alternator, i swapped thw wire onto the bottom of the two terminals and this caused it to charge! battery light off, perfect..

Tidied tools up, went and had a shower, went into town for food and on the way home the light came on and lights got dimmer and dimmer then all my ignition lights came on and i had no power steering..

Took it to a garage and they said it was a dodgy alternator (seemed strange to me how it had already had 2 in the last 6 months) but anyway, i told them to shove another alternator on.

This is charging to 14.3 volts but it will not put the battery light out???

I had a replacement on a 54 plate astra, turns out it was listed wrong in the factors catalogue. the modern ones tend to be controlled by the ECU. It sounds simmilar to what your issue is. I ended up phoning the help number in the alternator box and they told me I had the wrong part. Fortunately the factor sorted it and they even sorted the garage to replace it.