MK2 GOLF Alternator Problems

I recently changed the water pump on my golf mk2 1.6d. Unfortunately when testing it, i found i was runnning the alternator with no leads attached, oops.
I have bought a reconditioned one from a well known company, it looks exactly the same, with the same B+, D+ and W terminals on, so it is definatley the correct part, however now I have connected it all up with the drive tightened the battery light on the dash is on. I have only run it briefly so as not to damage the new one.
Could this mean the voltage regulator that I took from the old one is broken or something else.
I did fit a second hand alternator briefly which didn;t have the right mounting brackets but did have the correct terminals and the same thing happened, although this had a different voltage regulator on.
Can anyone help? Thanks (sorry about the long post)

If my reading of other information is correct, then the Bosch plan for a voltage regulator is to de-energize the rotor when overvoltage occurs to regulate the voltage produced. If this is correct, and your voltage regulator was not connected previously, then you may have been overcharging your battery. Did you have to add water to it regularly?

Sounds like you need a new voltage regulator. Particularly if you were trying to use the old one. The brushes on the old one would certainly be worn, and replacement would help a lot.

Another thing to consider is the wiring of the connectors. Any changes there? If someone had to repair it, there's always the chance they switched wires.

I have not had the car for very long or driven it much so have not had to add water.
The reason I replaced the alternator was because at idle with all electrics off the battery light would flicker, therefore I assumed it would just get worse so I just got another alternator. Now even if I rev it a bit the battery light is on all the time.
All the wiring is back on the appropriate terminals, and the terminals on the battery are secure, also there is no belt slippage. I'm worried as I'm driving the car to africa from the UK in 4 weeks.

Edit: wasen't talking about the regulator in the first post, sorry. it was a small black plastic cube with a connector coming out of it. Not sure this is the problem however as I'm pretty sure it was working on the old one.

is the blue cable connected ? it supplies voltage to jump-start the alternator and also turns the dash batt light off.
I would just change the regulator , they are cheap.

I would guess the regulator too, but I just wonder about the thought off turning the alt without wires ruining it? I have had some bad luck with my mk1 rabbits alt leads coming off (thirty year old spade connectors finally going POOT) and I ran the car for a couple hours like this on the highway before I noticed I had to turn the car off and re start it a few times going from place to place to find new ends, but once I re plugged the alt back in it worked fine.
my guess is that the regulator was bad to begin with.

I would have replace the regulator from the get-go, since that's generally what goes out on the alternators. If it's like the ones I'm familiar with, the regulator is attached to the brushes, and when the brushes get worn, it produces less power.

The alternator attached now, is a new reconditioned unit with a 12 month guarantee. I would have assumed they would test the unit before they sell it.
I will have a look at the blue connector, as it may be that it has somehow become frayed or is not connecting properly.
Thanks

I have heard several of instances where "rebuilt" alternators do not work.

Also the B+ wire (and all of them for that matter) that connect to the alternator are subject to severe vibration and can break inside, near the terminal end. This happened on my '85 and I had to splice a new wire and connector on the "W" wire. Something to check

--Nate