I thought I would make a post about how I went about repairing the wiring for the reverse light switch. This seems to be quite a common fault and from reading other posts you cannot buy a new connector that goes into the switch, so I went about repairing the wiring to mine rather than soldering the wires straight onto the switch itself. This means that in the future should it be required you can disconnect the switch as originally intended if carrying out work.
My pictures are from a 2004 147 JTD Mjet 16v with 6 Speed gearbox.
1. I located the switch and connector on the top of the gearbox. If you go to the back of the battery and look down you should be able to see it. All you need to do is unclip the securing clip and pull it out. Easier said than done, I managed to do this without removing the battery and tray but I have really skinny arms.
2. By the time I had removed the connector both of the wires had come off (I think that someone has previously done a running repair on mine). Unfortunately the wires had broken off as close to the connector as you could get, not leaving me anything to re-solder too. So I had to dig out a bit of the green rubber covering to find some more cable that I could solder onto. Also I could just make out the colours of one of the cables on the connector and so on my model could see that the wire that was partly blue went to the no.1 position.
3. I soldered the two new wires on. Not a pretty job but it works. My wires were about 15cm long, but if I was to do it again would make then no more than 10cm.
4. Then I covered my work in glue. I did this for 2 reasons. Firstly I had to dig out some of the rubber that stops water penetrating the connector so had to fill it in. Secondly and the reason why I have built up the layers of glue was to give some extra support to the joint. Obviously the connection between the wire and the connector is the weak point (especially now as I have soldered it which makes it strong but rather brittle) and when the engine vibrates then this is going to be the part most likely to break, so by covering it in glue I hope that it lasts longer.
5. The next task was to connect my newly repaired section to the loom. I chose to solder it, cover the connection in shrink wrap and then used insulation tape to bind it all together. Hopefully water wonít be able to get inside and it looks a bit neater too.
6. Finally it was time plug the connector back up and test. After an hour of fiddling around with the tips of two fingers I really wish I had taken the battery out to give better access. However, I discovered that moving the brake and clutch fluid reservoir an inch towards the drivers side gave me slightly better movement and eventually got the connector back in.
7. After checking I hadnít left any tools lying around the engine bay (you learn from your previous mistakes!), I turned on the ignition to test, and thankfully it worked. Now time will tell how long for!
In summary, it is a straight forward job as long as you are happy to use a soldering iron, but the fiddly bit is getting to the connector on top of the gearbox, but should be easier if you remove the battery and tray.