When I left the car on Saturday we had no dipped beam, and no rear fog-light. Also, the switches didn't illuminate when the headlights were on. Probably all related and something simple.

Over 2 hours later and I worked it out. I tried bypassing switches, I tried everything. There was no fog-light. I checked the signal into the switch which was +12v. I tried bypassing the switch to eliminate this from the problem, but still no fog light.

I was even getting power into the fuse box, but not out of it. The fuse was fine though. It turned out to be that one of the cables underneath the fuse box was not seated correctly, but I only noticed when I removed the fuse box (which is very fiddly at this stage). Fog light fixed - now for the dipped beam problem.

The dipped beam is a similar problem. The switch is getting a +12v signal, and again I try bypassing it but still no joy, so the switch is fine. Again, the switch is putting out +12v too, but the fuse is not getting any power.

I checked readings from all around the car. Eventually I decided to look at the giant block connector that interfaces the dash loom to the main loom. One of the pins that connect the block was bent and had been pushed right back and so did not seat into the other terminal. It could have been hours before I checked this as it was Westfield-made and so I didn't expect it to be a problem. I recovered the pin with pliers and once reconnected it worked fine.

Still no instrument illumination though, but that's because I forgot to connect the orange/red and black wires to each of the switches. Easy fix!

Although it was a silly problem and cost a lot of time, I really enjoyed the electrical investigation.

I started to look at the ECU tray. I fitted the hinges into place and drilled a couple of holes. It's getting late now though so I'll finish it another day.