Fuse Block On Top Of Battery.......

[BUGSTUFF]

Two questions for those of you that have had the fuse block on top of your battery melt because the cooling fan fuse burned up:

Did you ever find a concise reason as to why the fuse overheated?

And, after you replaced the fuse block, has the problem happened again?

After 9 years and 75,000 miles, ours melted the other morning. I put a new fuse in, limped the car home and replaced the fuse block. I also replaced the OEM 30 amp fuses with some aftermarket 30 amp Buss fuses. Everything is working correctly (fans, ABS, etc) so I'm hoping the problem won't happen again.

Thoughts & comments???

[noR]

I haven't replaced any of the fuses or the block yet. ...

Let me know how it goes?

I did have a fan problem that caused the issue. Replaced the fan a while back, haven't messed w/the fuses yet though.

[OldSkoolVWLover]

the cable that comes from the alternator was not giving consistent amperage, spiking causing the fuse block to have problems. Replaced the cable and the fuse block.... so far so good.

[BUGSTUFF]

OldSkool,

How did you know that the alt. cable was bad??? And how much did it cost to replace???

[OldSkoolVWLover]

took it to the dealership and had em diagnose it.



Our was a lil bit of a mess, because the PO (or crappy dealership we bought the car from) wired around the fuse problem (I didn't notice this when we bought the car). So the AC and everything worked for the first month or 2 we had the car (then it was winter), the following summer no AC. We figured the car was just old and might have had a leak, so we took it to the dealership and found all these issues when they got into diagnosing the AC issue.

Where the factory fuse panel had been wired around they had used a smaller gauge wire, with inline fuse holder. Because of the spikes the plastic on the wire had melted, the plastic fuse holder melted and the freaking plastic on the fuse had melted a lil.


In the end we spent about 400 IIRC to get everything fixed. The cable wasn't too expensive (I don't have my paperwork easily accesible since we moved and stuff is still all over). If I find it I will post up my price for the cable and the part number.

[jiggseob]

The fuse block melted and obliterated three fuses.

The problem seems to be corrosion on the non-copper (some cheap alloy) fuse contacts in the fuse block.

When the cooling fans come on, such as when the A/C is on, there is like 18 amps going across a 20 amp fuse. The current is below the fuse rating, so the fuse doesn't blow. But the knife-edge of the contact against the blade of the fuse is a small contact point, and it heats up and burns, especially if some corrosion builds up. Then it burns, but the plastic doesn't really support combustion, so once the current welding on the fuse blade stops adding heat to the fire, the fire puts itselft out.

All of this happening on top of the battery, which from time to time burps explosive hydrogen gass...

I replaced the fuse block, and use a dab of Kopr-Kote anti-seize compound on each fuse blade as a contact improver and corrosion preventer. No problems since then, 220,000 kms ago.

Mathew Banack
81 Rabbit Pickup LX diesel
98 Beetle TDI
03 Jetta Wagon (wife's)

[Tearstone]

Just replaced the 30 amp fuse farthest to the left tonight. One of the connectors had melted the plastic around it and the fuse came out in pieces. This car is full of surprises.