Charging problems!

Hi there,
I've seen through the posts that this looks quiet a common problem but mine has a twist, I have gone through a few alternators as have many others with charging problems, but this time the new alternator didn't solve the problem. I took it back and got another new one and it also did not fix the problem. I had the alternator tested and it checked out fine twice. I tried three different batteries and all three have tested fine also.Now heres the twist, I was told to start looking for wiring probs/shorts so i did. I found what looked to be a problem at the starter. There were four wires going to the starter solenoid (Not counting that little wire all by its self on the smaller bolt), the large battery wire ( It looked ok). One black wire with red stripe in it which came to what I think was a fuseable link then it changed to a smaller orange wire before it got to the starter (Looked ok) I think this one came from the alternator. Then there was a red wire which went into a fuseable link and changed to orange on the other side then went into the starter (This wire where it was red was bare for about 5 inches and the copper was all green on it and weathered looking and some of the strands had broken loose where it went into the fuseable. The last wire was another red wire going into a fuseable then turned orange coming out before going into the starter it also looked except for a small nick in it which showed the wire inside for about a quarter inch. I was messing with these wires for a bit and when I was done the one large black wire with the red stripe that turned to orange on the other side of the fuse dropped right out of the fuseable link (On the starter side) and the end looked as though it had rotted off or something it had all the green old looking stuff on it like old copper wires get. What I need to know is What is this wire for? Could this be be causing the car not to charge? Could this be the missing link which is frying all the corsica alternators? Any and all replies would be greatly appreciated. Thanks.

Well I got it already, turned out that it was the wire which runs from the alternator to the starter that was bad. Couldn't tell to look at it but when I was fiddling with the wires to the starter the wire from the alternator dropped right out of the fuseable link, it looked all corroded at the end which came out of the fuseable, when i looked down into the fuseable it to looked somewhat corroded inside. Just thought I would post the outcome in case anyone else has somewhat the same problem and cannot see it. Don't ya hate when ya find a thread with the same problem only to read to the end and see that the fix was never told?

Any wire that the insualtion has been burned through should be replaced. If the wiring inside is corroded (green and chalky) it should be replaced.