On my MKIV Jetta the wire going to S177 is getting super hot an melting my fuse box, an im talking from the time I start my car to pop my hood the fuse box cover will burn your hand. Anyone know why this is happening? I used a voltage meter an it reads 14v but the wire running from the fuse box to the alt gets super hot, an it only gets hot on the side of the fuse box. Could it be a bad alt?
Car in need
This is very prone to melting. It's a known issue with our cars. It tends to melt around the three green buss fuses located in the box. When it finally melts you will lose you cooling fans and start to get a weird collage of symptoms. Replace the box when you start to see it melt.
Last edited by VdubXXIV; 08-13-2010 at 10:24 PM.
I have seen a bad alternater cause this along with alternater cable and even most recently i had a walmart battery cause the wiring to get hot in a car.
The most recent was a 2004 1.8t jetta had a walmart battery. replaced the fuse panel, battery and power cable to the alt. fixed it.
just had this happen. i think it happened along with my alternator going dead because i had dead alternator symptoms and the box was found melted when they did the alternator service. my starter was doing the squealing that all VWs do and they replaced that while they were in there. said it also could have had something to do with my sub-woofer but it's only a 760w and it doesn't stress the power system at all... the lights dim more from rolling the windows up and down and not at all from the amp.
This is definately the alternator wire. I have replaced 2 boxes before i figured out what it was. I sloke with a vw tech and he explained to me that over the years the wire begins to build resistance and that means higher temps. 177 in that diagram goes directly to the alternator. Not the starter. Replace the alternator wire with any 2 gauge battery wire from advanced auto. I used a 4' negative cable so it would be the same color as the original. Ive been melt free for over a year now.
like i said, the 177 runs fron the fuse box, under the battery, through a black clamp that holds a few different wires, and it continues under the intake manifold to a bolt on the side of the alternator. change that alternator wire. it has alot of resistance and is getting extremely hot. the box costs about $100. if you dont replace that wire that only cost $10 with it, you run the risk of melting that box AGAIN (like i did) and having to buy yet another box. do yourself a favor and take it from someone that has had this issue first hand.
I recently had this same issue-- A couple days before my car quit, the check engine light went on. I ignored it thinking it was probably the O2 sensor... two days after, the abs and airbag lights came on and 10 mins after that my car lost power.
I was able to coast my car right to a sears auto store parking lot (sunday night...)... and being that I do not have a ton of experience I felt pretty lucky! No need to tow.
They said it was my battery (wrong), charged me $120, and sent me on my way. Later that day car quit again, this time 2hrs from home. I ended up at a nice little shop that helped me learn more about what was happening w/ my car- they found that it wasn't the battery, and the alternator was running fine... so I found this thread, which helped us fix my car.
Thank you! I changed the cord and used a negative to keep it the same color. We rigged it so it works, but it's connected directly to the battery w/o a fuse. Which I KNOW is not good, but it's running. I am looking for a new junction/fuse box and am wondering this... does it matter what year the part is from? I have a 2004 Jetta wagon 2.0.... and I'm thinking they have to be the same from certain years... any input?
I had the same problem with my 2004 Jetta. The first fuse kept melting. We would replace it and it would happen again. We finally took it in to the dealership and they said they alternator harness was giving off too much power so they replaced it and we haven't had any problems since.
i had the same problem too, went to a audio shop and got some nice 2 gauge wire and replaced the the wire coming from the alternator to the battery.
The dealer wanted 100+ dollars for the original wire, I spend 20-25 on 12ft of a really nice stinger wire.
It took me a few hours, but my custom wire is better than the original wire.