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Loss Of Power - Fixing The Fusible Link

#1
Recently I was driving along and suddenly lost all power to my k12 micra. Nothing worked, not even the hazard lights or central locking. It was as if someone had just pulled the plug out of the mains on me. After looking on this forum I found a few people who had the same problem and were able to offer a solution... So this is a more in depth with pictures description of how to fix this seemingly common problem yourself for FREE!!!

For those who want the short story:

Remove fusible link.
Clean corrosion off.
Solder broken link.
Put back in car.
Car works again.

For those who want the details keep reading...

The (weakest) Fusible Link

As someone already mentioned on one of the threads the fusible link is a possible cause for loss of power. I have heard of some people scrapping their car when this happens because they can't figure out the problem, and they take it to a mechanic who also might not know as this is an electrical fault not mechanical (and very easy (and pricey) to overlook). Anyway, I pulled the cars circuit diagram off the internet and could see there are 3 main fuse boxes on a micra. One of these contains the fusible links and is attached to the positive battery terminal/connector (under the red cover) as shown in the image below .

View attachment 57771

Looks pretty unassuming right? If you didn't know the fusible links are basically just metal strips that carry an electric current across them and are designed to melt so as to break the circuit if there is a power surge or too many amps across the terminals. From my research I discovered corrosion of this part is a very common problem especially in Nissans, and in fact i believe there was a recall on some earlier models because of it. It's actually a bit of a design flaw on Nissans part as one of the five links carries the entire electrical supply from the battery and if it breaks you loose all power and i mean everything!

But anyway, the box is removed simply by disconnecting it from the battery (always disconnect negative side first and cover the negative terminal with a cloth to prevent accidental arching) and unscrewing the bolts that hold the wires in place. The bottom wires are push fit and pop out with a bit of jiggling and patience. You should see a transparent plastic screen that has the fuse sizes inscribed on it covering the links. This can be removed (carefully as i snapped mine) and you should be able to see your fusible links in all their glory like i did below.

IMG_3493.jpg


As you can see, the green blue stuff is corrosion that has slowly been eating its way through the metal components over the course of the 14 years I've had the car. Finally it must have broken all the way through. NOTE: This failure was from corrosion. If your link is broken and you can't see why you should get it checked by a professional.

I started chiseling it off with a screwdriver and cleaning the surface with white spirit. After a fair while at this i got most of the corrosion off and could clearly see where it had caused the link to fail. I scrubbed it up to get as much of the corrosion off as possible. See the image bellow.

IMG_3501.jpg


At this point I could either pay £50 for a new link (probably sensible) or DIY it! You can guess what I chose. I got my soldering Iron out and put a big blob of solder to rejoin the link. WARNING: Fuses are designed to break for a reason. Fuses should only be re-soldered if you're a cheapskate like me and like to live life on the edge!

IMG_3502.jpg


The image above shows my masterpiece (Yes my soldering is excessive and ugly but it does the job). As i mentioned earlier i acidentaly broke the plastic cover off in a fit of rage and so wrapped some electrical tape around it too keep it together. The image below shows this when it was reinstalled.

IMG_3505.JPG


After everything was back in place I put the key in the ignition and BAM! She roared back to life as if nothing had ever happened.

On a side not, I did eventually buy a new fusible link just in case my handy work didn't last but when it came it had completely different fuses to the ones on the listing and the ones my car needed so I couldn't use it. Luckily I haven't had to remove my repaired link yet and everything is running beautifully!

Hope this helps someone and saves them from a lot of misery and money!
 
#2
Nissan cheap & nasty unfit for purpose piece of plastic cover that does not keep out condensation & or water ingress is the source of this well-known K12 electrics fault.

Quote; “3-3-2012: Notorious fault is severe corrosion of the fusible link holder, which is situated underneath the nearside headlamp unit. Rated at 30 amps, this piece of cheap and nasty, plastic framework (costing £64.97 ) suffers from very poor design of the waterproofing housing which results in moisture build-up inside the housing”

Item number 7 of the long list of K12 faults in the good/bad section as follows.

Reference; https://www.honestjohn.co.uk/carbycar/nissan/micra-k12-2003/?section=good

Therefore waterproofing & excluding damp/condensation is key to resolving this issue with damaged plastic casing.

Good luck. (y)
 
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