Originally Posted by Cire1166
Sorry for the delay, I've been out of town a lot and just now have been able to get under the hood of the Jetta. Checked the fuses first. When checking the fuse block on top of the battery I discovered a corner of it melted. It was the top left corner with the thick black wire. The fuse itself was in tacked but black and all crapped up. Iím thinking this could be the problem but why would this happen? Could the fuse block just get old and go haywire or is there some other issue lurking around. Anyway your help is greatly appreciated.
This is quite common. You will probably want to change the fusebox I'm afraid. Also, the thick cable that attaches runs down to the supply from the alternator. The end with the crimp lug goes bad and develops a poor connection between the crimp and the cable. You get a volt drop across the bad connection and with time the cable at that end gets hotter and burns the cable up and keeps getting worse until its getting so hot it eventually melts the fuse box. I think they changed the design a little in 02 - you may have got the earlier variety I think.
The cable is part of a small harness from VW and it might be best to change the whole thing rather than just the thick alternator cable. If you are good with electrics and have a large enough crimp tool you could make up your own cable down to the alternator. You have to use some really beefy wire on that connection. I think that fuse is rated up around 100Amps or so , I'd have to look up the value to be sure. Needless to say, I don't think the fuse box or harness are cheap. Don't just change the fuse box without replacing the cable or it will just melt the fuse box again. It may be possible to cut back your existing cable insulation until you find nice shiny copper wire then cut the cable and reattach a new crimp at that point - but you'd need to check the resistance of the cable is less than 0.4 ohm or less I think.
I'd be more inclined to change the harness and fuse box and be done with it.
Make sure you get all the connections tight on the alternator and fuse box.