Aribert :
My guess would be that your 10 amp fuse or holder developed some
corrosion, with attendant high resistance, and excessive heat
generated. This tends to be a vicious circle, as the heat encourages
the corrosion, which encourages the heat, etc. until total failure.
High underhood temps may have contributed to the original corrosion, but
not necessarily. Since heat is related to power, which is the product
of voltage and current, a bad connection at 10 amps can easily generate
far more heat than a good connection at 35 amps.
I've found that a thin coat of silicone grease (the kind sold in
electronics shops as 'dielectric grease' will do) helps greatly in
preventing corrosion in electrical contacts, especially ones where the
tin plate has worn through. Unfortunately, it attracts dirt like mad.
There are also products made specifically for this purpose, but I
haven't tried any yet.
Consider it your latest sacrifice to Prince Lucas !
Randall
Aribert_Neumann@magna.on.ca wrote:
>
> About 3 weeks ago my 71 GT-6 lost front parking/marker lights. About a
> week later I discovered that the dash lights were out also. At this time
> the rear tail/side marker lights were still functioning. A few days ago I
> also lost tail/rear marker lights. THe car was now definitely broke enough
> to fix. Problem was fuse related. Here is the puzzlement: My Bently
> manual calls for a 35 amp fuse for all three circuits. Since only the
> running lights (no headlights, no aux. feeds) are on the center fuse, I
> derated to a 10 amp fuse (years ago) with out any problems until now. THe
> cause of my light failure was that the fuse box ( secifically the plastic
> tab that supports the clip (that the wires are crimped to) that in turn
> contacts the fuse) had MELTED and the plastic had actually flowed between
> the fuse and the clip. Since the system was spec'ed for a 35 amp fuse, why
> would it get warm enough to melt the plastic with only a 10 amp fuse. BTW,
> the 10 amp fuse is still funtional. My only guess is that the 10 amp fuse
> is defective. I scraped the melted plastic off of the clip and inserted a
> 35 amp fuse (and a sliver of wood between the clip and the melted plastic
> tab to provide good electrical contact between the clip and the fuse) and
> the electical system is funtioning well. One last bit of info - my engine
> compartment is very hot - 2.5L and headers. I do not think this has
> anything to do with the melted fuse box, but a few weeks ago after being
> stuck in first gear traffic for about a 1/2 hour, I noticed a stream of
> heat entering thru the fire wall. I removed my sandal and when traffic
> sped up I searched for the cause with my bare left foot. THe source of the
> heat was a loose rubber boot on the clutch linkage and the result was a
> foot that got lightly burnt from the hot air and that was tender for the
> next hour.
>
> Speculation as to why the fuse box melted and suggestions on how to trouble
> shoot a system that appears to be ok
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