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Discussion Starter · #1 ·

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?

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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.
 

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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.
 

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Discussion Starter · #11 ·
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.
It's just weird that this is happening cause I really havnt drove the car an all of a sudden this happens I did put an upgraded battery in it cause of my pumps. But I can't see that being the problem
 

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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.
 

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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.
 

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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.
 
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