DaveFJ
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| posted on 30/5/09 at 02:59 PM |
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Fuse melting but not blowing
Ok chaps and chapesses....
a couple of months ago a 15amp fuse went and i lost all my instruments....
changed the fuse. no problems...
however today my car overheated because the fan didnt kick in.. thought i would check the fuses and that new 15amp fuse had melted!
it hadn't blown but the plastic has completely melted?
(not saying that the fan is on that circuit, i have no idea what circuit thats on!)
So.. how does that work? how can the fuse plastic melt and the fuse not blow? 
the only change i have made recently to the guage wiring is put a toggle switch in line to the oil pressure guage and connect a second sender from my
fuel regulator so i can switch the guage between fuel and oil pressure... surely that cant be the cause?
[Edited on 30-5-09 by DaveFJ]
Dave
"In Support of Help the Heroes" - Always
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bitsilly
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| posted on 30/5/09 at 03:10 PM |
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Strange you should post this now, as I had the same problem a while ago.
All I could imagine it was was a limited (dirty) connection on the spade of the fuse. If so I figured all the current flowing through the restriction
would heat the metal up, then the fuse casing being plastic and nearby melts, but as the current is still less than 15 amps it doesn't blow the
fuse.
Bottom line is that if the current exceeded the fuse amps, the fuse would blow. On mine it didn't.
Course all thats a guess!
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DaveFJ
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| posted on 30/5/09 at 03:27 PM |
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wel just replaced fuse and ran her up to temp.. got fan going then pulled fuse and it didnt stop so i guess the fan problems werent connected...
odd because i have done nothing else and now the fan is working again...
bl**dy electrics!!!
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BenB
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| posted on 30/5/09 at 03:34 PM |
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My old tintop (Nissan Micra) did this all the time because the fuse holders were made from rubbish metal so they went rusty. When they went rusty
their resistance increased and they then produced lots of lovely heat when the juice was flowing through them. Answer= new fuse holder.
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Xtreme Kermit
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| posted on 30/5/09 at 06:51 PM |
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It sounds like you have dirty conacts to the fuse. This will casue high restistance across the fuse and the temperature will go sky high.
Could be worthwhile checking the fuse is seating properly.
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