Hallelujah, hallelujah, hallelujah, hallelujah, halleeeluuujah.
Changed my car just before Xmas, so I needed a new towbar. Thought I would save a few quid by fitting it myself. After hours and hours of scrabbling around under the car on the garage floor over the past fortnight and many more hours of head scratching with wiring diagrams, relays and a voltmeter, the thing is finally on. And all the lights on the lighting board actually work!!
Note to self : Pay somebody else to do it next time....