Friday 26 June 2009

Light switch

So I'm ready for the MOT tomorrow, but at the last minute I noticed that the dipped beam wasn't working, only full beam. I checked the wires to the back of the bulb and everything was in place. I then partially removed the switch and found that if I jiggled it around a bit the lights would work, and then not work.

Dismantling the switch revealed some rather poor quality workmanship - more like a GCSE electronics project than a commercial automotive part. The dismantling process indeed revealed the problem (see later), but rendered the switch useless. I went round the corner to Fanatic to get a new one, armed with a multimeter to ensure I got a working one.

Now there is definitely a technique to getting the switch cable in through the throttle housing - remove the tough plastic sheathing so that the individual wires are loose and exposed enough to be fed through one by one and captured at the other side. I'd say its about 100mm or so. Then feed each wire through one by one, and when they're all through a combination of pulling from one end and pushing with a blunt instrument at the other end should get your wires through. Make sure when you're done the bulk of it sits in the recess to the front of the housing. Test your throttle, and if there's too much resistance from your light wiring then jiggle it around a bit more or even try some WD40.

So after fitting my new switch I had the same problem all over again - some settings work, some don't. But armed with some prior knowledge I now knew how to overcome this. With the switch fully fitted take each individual wire where it appears from the sheath and pull it hard. This pulls the wire within the switch housing so that it sits squarely back into its correct position where it should be soldered, but often isn't.

Problem fixed. Ready for MOT. Note to self: buy a better quality switch soon. :)

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