Ford tractor ignition switch wiring diagram guide. The correct diagram depends on the series, voltage setup, and terminal arrangement. Getting that match wrong is the root of most wiring problems after a repair. Terminal B feeds battery power in. IGN feeds the ignition circuit out. A powers gauges and dash circuits. S sends the start signal. ACC powers lights or accessories. G is ground on some models. On 9N and 2N tractors, many have been converted from 6 volt to 12 volt. That changes coil feed routing and resistor use. On 8N tractors, early and late models use different layouts. The serial break is 263844. A converted 8N should have its own diagram. For 601 and 801 tractors, the run and start circuit is more developed than the earlier N-series. For 2000 series tractors, confirm the engine configuration and fuel type first. Test voltage at B, IGN, and S before startup. Check continuity through the safety circuit. A tractor that only runs while the key is held over usually has a misplaced run circuit.