I am just testing out all the electrical circuits on 4376R after fitting a new loom. This is not a job for the faint-hearted.
After charging up and connecting a new battery, I turned the ignition switch to see what would happen and nothing, not a squeak.
I traced the white with red wire from the switch to the starter, and the wire was continuous.
I tested the voltage of the thick brown wire at the ignition switch, 12v as you would expect.
I took the ignition switch apart, removing it from the key part in the column, and disconnected the wires on the back, tested the connections, and they all seemed to work. You need 3 hands to do this, hold both meter probes on the contacts, hold the switch, and turn the switch with a screwdriver. It is possibly but very difficult with only two. An octopus would find it easy.
So last resort, test the voltage at terminal 1, the white/red wire to the starter. 12v from the thick brown reduces to 6v coming out of terminal 1. Time to pull the switch apart.
There are 3 crimps on the aluminium case holding the terminal plate in the body. Ease those apart with a screwdriver, then move over a clean surface, then carefully pull apart, expecting things to spring out.
It was not too dramatic, but the terminals which make contact when you turn the switch, were horrible. I got some fine emery paper, and rubbed the contacts on the paper until there were all gleaming. Carefully put the switch back together, now there is only 1 position it all fits together, crimp the three cut outs to hold the plate to the body, mark the terminal connectors on the metal body, 1,2,2,3,3,5,5, connect the wires, reconnect the battery, and try with a screwdriver. Bingo. The starter turned over well with the plugs out, but no oil pressure. The battery went flat before oil pressure registered. Leave the battery on charge, and try again tomorrow when my brain recovers.
Next ignition switch problem, has anyone managed to find someone who has all the ignition keys, or does someone know a locksmith who can get a key to work in the ignition switch barrel. I have a few barrels without keys to fit, and the whole ignition switch/key assembly is very expensive.
Back in the day, my local garage used to have all the door and boot/trunk keys for minis, so they were available, I just need to find who has the set for ignition locks.