Melting fuses WHY?

[mikesz]

a couple months ago my 99 boxster just died out. had it towed to the dealer and the fuse for the fuel pump melted to the fuse block. Dealer order new fuse block and replaced the block for the fuel pump and car ran fine for a while. Also, a couple weeks prior to that the fuse for the heater blower melted too but I was able to get it out and replace it. Last week we are driving and my coolant light is flashing, was able to limp home. One of the fuses for the coolant fan tripped and the other melted so now I have to replace another fuse block in the fuse box. Any ideas what would cause this? The dealer said the buse block looked like there was some corrosion on it and I noticed too the blades on some of the fuses looked corroded maybe dampness? Anyone know the part numbers for the fuse blocks, the piece that fits into the fuse box where the fuse pop into? I am trying to get another fuse block from someone who is parting out theirs. I have never seen this happen before.

[Loren]

Further inspection and more information about the city climate you live in.

Have the cars drains been cleaned?

Any electrical mods? i.e. radio, nav, etc.

A photo or two might also help us understand what is happening...

The fuse holders are 999 650 209 40 Fuse block -- US MSRP $8.98 each

[mikesz]

I live in RI. It has been exceptionally warm past couple of weeks but when the Heater fan and fuel pump fuses melted it was much cooler around 40-50. No electrical mods factory radio, no nav. I have used compressed air to make sure drains are clear in fact when I wash the car and pull it into the garage there are puddles right behind the front wheels where, I think the drains are.

[mikefocke]

Fuses blow because there is too much current going through them. Generally a bad connection, So the question is with 3 sub-circuits blowing, what could be the common element.

Voltage regulator? Ground?

[mikesz]

Thanks Loren, I ordered the parts and will replace once I get them. MikeFocke, will check ground. I think once I replace the fuse block going to find a good auto electrical shop and have them take a look.

[mikesz]

Figured it out. I determined the right cooling fan was not working at all and was causing fuses to blow. I replaced it. When I got it out I could tell it was binding. Once I replaced it the fan worked fine. The left fan would only work on High speed. So I imagine the ballast resistor was gone but I replaced the entire fan assembly with ballast resistor. Once I did this it too worked correctly. I figure this out by taking out the relay's and using a jumper wire to test. When I did this the fuses would blow right away. Next thing I will check using my Durametric is the engine bay cooling fan.

Thanks all for your help!