Husqvarna ignition switch wiring diagram. A Husqvarna ignition switch wiring diagram typically has a few key terminals. B is the battery. S goes to the starter solenoid. M controls the kill function. Additional terminals may be used for lights, accessories, or ground. If the mower won’t crank, cranks without spark, or blows a fuse after a new switch, the switch is probably not the real problem. In OFF, the M terminal may ground the kill wire to stop the engine. In RUN, power feeds the accessory or lighting circuit. In START, B connects to S and sends power to the starter relay through the safety switches. No click usually means an open safety circuit. Crank but no spark often points to the kill wire. Check the PTO switch, brake switch, and seat switch before replacing the ignition switch.