VR Alternator issues

[mumto2bratz]

Hi,
I have a 94 VR Lexcen Wagon, We had issues in November last year where we were told we needed a new battery, got a new battery, worked ok for a month or so, Battery light came on again, Got a 2nd hand alternator out of a working VR, again lasted a week or 2 (hubbies mate tried the screw driver to ear and the bearings were stuffed) put another 2nd hand alternator in it.. ran ok for about 2 weeks, then the battery light came on again. Took it to an auto elec and he said it's the alternator again!!!
We've change the Alternator 3 times, battery twice, fusible Link near the battery, today we changed the regulator and again it didn't solve the issue.. Battery light coming on and staying on.
Disconnecting the alternator (battery wires to regulator) and the battery light goes off, plug it back in and comes back on..
Any other ideas on what it could be?
Cheers

[VrWagz1]

The lesson here is possibly, buying cheap second hand parts can be a curse. To me i recon your first one was ok, probably just needed a new regulator. Put the new reg in that one and im sure it will be fine then. Check that the lug on the main battery wire on the alternator, make sure hasnt become burnt and creating a bad connection either.

[CRCinAU]

You know what? I had something similar - however I didn't swap and change anything. I noticed that behind the alternator, the main cable to the battery was green, corroded, burnt and in a *really* bad way. This means it was dropping voltage before it even hit the battery.

I ended up making a new wire from 200A oxygen free cable (the really nice bendy stuff) and some brass. I soldered the wire onto the brass strip and drilled a hole in it the right size for the alternator, hooked it all up and everything has worked perfectly every since.

The moral of the story? The lead between the alternator and battery is critical - if it starts to fail, you'll have all sorts of strange problems. Start there and work your way up/down the chain and see what you can find.

[mumto2bratz]

Thanks for the help guys, will get out to it tomorrow..
I spoke with an auto elec and he has suggested that it could be the BCM or ECU.. hopefully it's just a series of bad alternators!

[CRCinAU]

Sounds like changing the most expensive parts first! :P

[VrWagz1]

DON NOT replace the BCM or ECU, as if they would be causing the problems your experiencing. In my experiance, only mech's who truley dont know much about electronic ignition systems do this, trying to blame the electronics. Its potentially the most reliable thing on the cars. Unless you done somthin stoopid with them.

[hako]

I'd go with what CRCinAU says - check the main cable to the back of the alternator - this can crystalise along the cable and appear OK at the terminal if it has previously been re-terminated. It can simply be replaced with a cable as CRCinAU says running direct from the alt to the battery. If this cable is dodgy, it may cause an intermittent connection which will destroy the alternator the same way that removing and connecting the main cable from the battery with the engine running would do. This is a cheap fix as only a length of thickish cable is involved.

[mumto2bratz]

Thanks for the advice guys, Changed the alternator today and no battery light.. mate said I should change the fusible link also.. that will be a job for another day... lol