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battery fuse box melting on 04 new beetle

87K views 44 replies 26 participants last post by  shaydogidog 
#1 ·
hello all,
i am new to the forum, and having a problem with my girlfriend's 2004 VW new beetle.
i have a 1966 mustang that i have restored, so i have some car knowledge...but the interworkings of a classic mustang are VASTLY different from that of a new bug, as i am finding out. everything is covered in plastic and it's hard to see what's going on under there.

with that said, i can see the problem, but am unsure of the solution...and even more unsure about the cause.
she went to leave this morning, and her car wouldn't start. sounded like her battery had died. so i popped the hood, got ready to jump start the bug, and quickly realized that there was a problem with the fuse box on top of the battery. the black wire looked like it had blown in half, and it had melted much of the plastic on the fuse box itself.

this is not the first time this has happened. she had this same problem last year, when we were living in maui. then, it was under warrenty, and she took it to the dealership on maui (cutter of maui, which was the only authorized VW dealer on the island, and was by far the world's worst car dealership....they have since went out of business). but since it was under warrenty then, we took it there and they supposedly fixed it. the guy said this was a common problem, and that they replaced the fuse box. i asked him what else they did...like "why did this short out in the first place" and he just shrugged and said these things happened, and that it was a common problem. so i think replacing the fuse box was sort of like putting a band aid on the problem, instead of really fixing it. because now it has happened yet again. unfortunately the car is no longer under warrenty, we are in florida, and the said service station is out of business.
and volkswagen customer service is completely worthless.

anyway, can anyone help? i've seen similar problems on this message board. is it that there's a short in the wiring somewhere? in particular, the black wire? i can't even see where the thing goes with all this plastic.
i figure i have to replace the fuse box....and what else???
help!!
thanks
 

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#3 ·
alright, so i ordered a new fuse box, and i ordered a new black cable (which runs to the alternator). the parts came in, and finally yesterday i installed them. car was still dead, so i jumped it and it started fine. drove around the block a few times, seemed to be running okay so i came back home and parked it. when i went to leave about a half hour later it was dead.
so i thought maybe i didn't drive it around enough, give the battery a chance to properly charge up. so today i jumped it again, took it out on the highway, drove at about 60 mph for 20 miles or so. should have been enough time to charge somewhat. pulled back into the apartment and killed the engine. tried it again. nothing. windows still work. radio still works. alarm seems to work. but the trip odometer and clock immediately reset themselves to zero once i tried to start the car, and it's acting just as dead as it did earlier....

is there anything i'm missing? is there any sort of "safety" features or anything that would disable the car from getting a jump start?
i wouldn't think it would be the alternator, because i don't think the car would have run that far on an already (almost)dead battery.
help!!
 
#8 ·
i was worried about the red wire too, but once i pulled it off and examined it, it looked fine. but the black wire was a real mess.

so, i called VW and they assured me there was no sort of safety feature, or anything else that should be keeping the car from starting.
so i figure it must be the battery. i called the VW dealership here again, and asked if they could test the battery. they said to bring the whole car in though, so they can charge me for a full diagnostic to look at it.
so i took it a sears automotive department, and they tested the battery and said it was low, but it wasn't necessarily bad. so they want me to bring the car in so they can test the system (at least they offered to test it for free, though)

i told him i didn't think it was the alternator, because the car ran fine for 20+ miles. and once the car is started it basically just runs off the alternator. he said that's true, but it's possible that the alternator is producing some current, just not enough...like enough to run the car but not enough to recharge the battery.

so i don't know. i'm about to take the car down there and have them test it. i hope it's not the alternator, because it looks like a real pain in the ass to get that thing out.
 
#9 ·
if the car wouldn't start do to a dead battery before you replaced the fuse box, it is still not going to start because of a dead battery. You need to either charge the battery with a battery charger for awhile or run the car for longer than 20 miles, remember you are not recharging a battery that is at 12 volts, it is probably quite a bit less than that, so it is going to take awhile to get it back up to full charge.
 
#11 ·
bummer

It sounds like you found your solution. I had an 04 that had a dead battery and the dealer told me (I had a guy at VW I actually trusted) that VW was trying to cut costs when they built that model and all 04s ended up with dead batteries at some point.
That car had 500 miles left on it's warranty when I traded it in for my fabulous 07 NB. I swear, smarter people made this car. I have 20k so far and the only problem I've had is the heater on the driver seat went out. LOVE heated seats! And my 17 inch wheels!!
 
#14 ·
When replacing the fuse box, can you just remove the red connection at the battery then swap out the cables or should you remove the negative and the positive cable before removing the fuse box ?
I believe we removed both (negative & positive) before replacing the fuse box on my '98. But it was in '04, so I'm not positive, my theory is better to be safe than sorry.
 
#13 ·
VW's OEM batteries are crapola--I have seen and heard of some weird things happening because of those batteries. Sometimes they crap out overnight, sometimes they hang on and do some wacky stuff. I dunno why. Had I seen this thread earlier I would've recommended replacing the battery right along with the fusebox.
 
#16 ·
red wire next to the black one is shorting out

somewhat same problem, the red wire next to the black one on my bug blew the fuse, so i replaced it and now after about 3 months something is drawing the battery down (this is where i narrowed down what was draining the battery)do you know where the red wire goes or what i can do next to find the short.
 
#17 · (Edited)
somewhat same problem, the red wire next to the black one on my bug blew the fuse, so i replaced it and now after about 3 months something is drawing the battery down (this is where i narrowed down what was draining the battery)do you know where the red wire goes or what i can do next to find the short.
I believe the Black wire goes to the alternator and it has been known to be a weak link. But you said you replaced the wire? Right? Or did you just replace the fuse?? That really doesn't solve your problem. You will need to change the entire wire with some better gauge wire or it will just keep on happening. Your battery draw could come from the bad cable as well.
 
#18 ·
Power distro panel melting

When i bought my 04 GLS a few weeks ago the power distribution panel was melted where the large red wire and the black wire connect. The PO had just bolted the two together and skipped the fuse. I bought a new panel and after just one day the whole thing was melted again. Earlier in this thread another 04 owner had the same issue and replaced the black wire which I believe he said was to the alternator. I have been searching online parts dealers and haven't found that wire. Is it a dealer only wire? And more importantly did it fix the real issue?
 
#19 ·
I ended up replacing the alternator wiring harness (52.00) at the dealer. And that did fix the problem - although from reading many threads I am sure it was only temporary. The real issue is the poor quality cable used. The solution is to replace the stock VW cable with a much better quality non-braided heavier gauge cable.
 
#21 ·
Try this first

For others checking this thread for melted fuse box! Save yourself alot of grief time and money! Don't change the alternator just yet...try this or have your mechanic do it. After changing the alternator and having the car die again I realized it wasn't the alternator. After noticing MY fuse box was melted {apparently a common problem)and much research it came down to a bad crimp connector. I couldn't even touch it because of heat, as soon as I turned the engine on! So I cut the old one off pulled the wire alittle bit and replaced it with a $2 dollar lug from Lowes and wahlaa. cool as a cucumber, no heat what so ever. DONE!!! don't spend money on a new alternator or harness till you try this!!!!

 
#22 ·
Try this first

For others checking this thread for melted fuse box! Save yourself alot of grief time and money! Don't change the alternator just yet...try this or have your mechanic do it.
After changing the alternator and having the car die again I realized it wasn't the alternator. After noticing MY fuse box was melted {apparently a common problem)and much research it came down to a bad crimp connector. I couldn't even touch it because of heat, as soon as I turned the engine on! So I cut the old one off pulled the wire alittle bit and replaced it with a $2 dollar lug from Lowes and wahlaa. cool as a cucumber, no heat what so ever. DONE!!! don't spend money on a new alternator or harness till you try this!!!!

 
#24 ·
THANK YOU newbeetle.org!

Sorry to bump an old thread, but I wanted to say that after a year of relatively trouble free bug ownership, this exact fuse box melting thing happened to my Lucybug. Searched around, this forum mostly, for ideas and THIS is what worked. Actually took this picture to Lowes, got the connector, clipped off the end of the wire, replaced the old connector and the wire is now not getting hot at all. Before, even after changing the fried alternator and other stuff, the wire kept getting hot with the car just started, and smoking hot once any fan came on. Can't believe the difference.

And I also changed the headlight bulb without wrecking anything ;) , so THANK YOU newbeetle.org!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

For others checking this thread for melted fuse box! Save yourself alot of grief time and money! Don't change the alternator just yet...try this or have your mechanic do it.
After changing the alternator and having the car die again I realized it wasn't the alternator. After noticing MY fuse box was melted {apparently a common problem)and much research it came down to a bad crimp connector. I couldn't even touch it because of heat, as soon as I turned the engine on! So I cut the old one off pulled the wire alittle bit and replaced it with a $2 dollar lug from Lowes and wahlaa. cool as a cucumber, no heat what so ever. DONE!!! don't spend money on a new alternator or harness till you try this!!!!

 
#23 ·
Repaired...

This problem on the vw beetle is a defect in the wiring harness going thru the firewall. The main red wire shorts out in the connector going to ground. If you test the wires, you will find this problem quick. It will cause a fire eventually, if this is not addressed asap. With this wire grounding out, it will drain a battery and can cause major damage to other components.
 
#25 ·
Another bump for an old thread. This issue rears its ugly head far to often. I followed the folks lead here and got the connector from Lowes. It lasted about a year and then the fuse box melted again. When our's melts it typically leaves the car stranded.

This time many other codes were thrown so I sorted them all out by replacing the CPS and the alternator. I also ordered a 4 gauge wire with a lug on one end. I picked up some parts at OReilly's and finished the other end myslef. I also replaced the fuse block once again.

And I am going to order a complete set of 2 gauge wires from: Innovative Wiring LLC

Here's hoping my fix holds up long enough to upgrade to the innovative wiring kit.
 

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#28 ·
The problem that causes the fuses boxes to melt is that vw or one of there supplies used cheap alternator cables that broke down over time which caused a lot of resistance in the cable between the alternator and the fuse box. The resistance in turn caused the heat that melted the fuse boxes. In my 04 I made my own alternator cable and I never had another issue with the battery top fuse box. And as far as the battery goes, every time you let a battery go dead. Below about 9 volts or so, you lessen the life of the battery by 7-10%. You kill one 4 or 5 times like that it will never be worth a crap. And modern day alternators don't put out voltage like the older ones did. I've seen several that wouldn't actually charge a dead battery. The battery would need charged with a battery charger and then the alternator would maintain it. With the introduction of AGM batteries they way alternators have traditionally charged batteries has changed.
 
#32 ·
I am about to have a shop manufacture an alternator charger cable with 2ga copper wire and soldered lugs on each end. Do you recall the length of the cable you used. Innovate Wiring sells a 50" long cable I'm just not sure if that length is correct for an 03 beetle. I know you have an 04, I'm sure they are the same. Would it be safe to have a cable made say 54" long to make sure? I cant imagine the extra few inches would matter in the resistance.

One more silly question, what ga. cable is the VW factory one?

Your help is appreciated.

Mark
 
#30 ·
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