Tuesday, 5 August 2014

Fuse Shenanigans

After my first (and hopefully only) breakdown caused by a blown fuse there was clearly an issue that needed rectifying to stop the fuse blowing in the future.  It turned out that it was the cycle wing repeater shorting the circuit and blowing one of the 10 amp fuses which killed the dashboard and a number of the other electrics too causing the breakdown.

Another Caterham owner I know suggested he changed all his fuses to LED versions, which illuminate when they've blown - what an absolutely brilliant idea!  I'd never had a fuse blow in a car so when I had the failure it wasn't really something I considered as the cause of the breakdown.

Anyway, I decided to buy a pack of these LED fuses John recommended.  They are fairly cheap on eBay, but wanting to get the job done as soon as possible I popped down to Halfrauds and bought a set.
LED blade fuses.
LED blade fuses.
This is a picture of a 10 amp LED blade fuse.  You can see the fuse wire in the middle, and you can also make out the LED towards the top.
10 amp LED blade fuse
10 amp LED blade fuse
Below is a picture of the fuses that I wanted to replace with the LED blade fuses.
Orignal Fuses in Caterham R500 Fuse Box.
Orignal Fuses in Caterham R500 Fuse Box.
It turns out the pack I bought from halfrauds didn't have enough 10 amp fuses, nor did it have any 7.5 amp fuses, so I had to take another trip there today to buy another pack and some 7.5 amp fuses too.  The only good point there is I have ALOT of spares now!  The fuses were removed with a set of needle nose pliers, as getting a good grip on them with your fingers can be a little fiddly.  I then fitted the LED blade fuses as you can see in the picture below.
LED blade fuses now fitted.
LED blade fuses now fitted.
Having fitted the LED blade fuses I was curious to see what sort of illumination a blown fuse would give.  My friend Matt is over from Australia at the moment, and we rigged up a piece of wire and blew a 5amp fuse over the battery terminals and instantly the LED lit - I couldn't believe how bright it was.  So I fitted the blown fuse to the fuse box, and you can very clearly see if a fuse is blown now - I'd say even with the fuse cover in place you'd very easily be able to see the glow from a blown fuse.  Considering the annoyance this extremely small part caused, I would highly recommend these... and a few spares too!
Blown 5 amp LED blade fuse illuminating fuse box.
Blown 5 amp LED blade fuse illuminating fuse box.
The next job was to check what was causing the issue of the blowing fuse.  Having had some grounding issues with the offside cycle wing repeater, I'd assumed this was the problem area.  Had a look at the connection block and the exposed wire along the wishbone and inside the body skin, and I couldn't really see anything that'd cause a problem.  A few posts on blatchat and 100% top marks to 'elie boone' who suggested the earthing screw in the cycle wing holder is quite long and has been known to pierce the live wire.  After loosening the wire and pulling a little out from the cycle wing stay, sure enough the live wire has been split by the sharp point of the screw holding the earth into place.
Broken live indicator repeater wire due to long earthing screw.
Broken live indicator repeater wire due to long earthing screw.
We removed the earth screw, pretty much cut it in half, so as to blunt the top and to decrease the amount of the screw protruding into the tube, insulated the broken wire shroud, fitted it all back together and hey presto one fully functional indicator repeater and no fuses blown - superb.

Only problem now is the weather has turned, so there's no track day at Snetterton tomorrow - and even worse the upcoming wales trip booked in for this weekend is also looking in jeopardy.

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