One of the puzzling things about owning any new car is working out where the minor controls are. Things like which side the wipers/indicators are, warning lamps, heater switches...
This is no less confusing on old cars. I have never really fully got to grips with Célestine's headlight switch. I knew how to make it work, for sure; turn once for low beam, turn again for high beam. This worked, even if there was a half second of complete darkness between the two.
Then one day I took the car to M. Musseau and asked about the indicators, and he showed me that the headlight switch, as well as turning, had a forward and backwards movement. Added to this, the sidelights (ultra low beam) which I didn't even realise I had weren't working at all. I looked at my Traction Avant book and found that indeed, I did have a forward and back. M. Musseau did some work on the switch, but never fully cracked how it should be wired.
On Sunday I decided to have a go myself, so armed with a schematic of the wiring, a diagram of how the switch should function and a couple of screwdrivers I started work. Taking the switch apart was easy, as was completely removing the wiring.
This is where my problems started.
The horns work off the same switch, but have been working properly, so I left them alone. According to the scematic this should have left me with 4 wires: 2 green, 1 red, 1 yellow. Instead I had six wires, and an additional red and an additional green.
This confused me, so with a piece of wire and Susan's assistance I sat and had an experiment, trying to work out which wires did what. This went well, although for ages I thought that two wires did nothing at all, until I realised that they light (very feebly) the dashboard.
I have now put the switch back together, and it all works well. Except for the dashboard lights, which go out when I put the headlights on high beam. This means I have another couple of hours of experimentation ahead of me, where I try work out which set of contacts I have wrong - which would be quite fun, and right up my street if I didn't have my mind on other things.