I've bought a couple of RF wiring harnesses from JD and they all work. Use a test light or a volt meter and see if you have 12v on the back of the ignition switch with the key held in the start position, you should have 12v on all 3 posts. The red wire is the power source, the pink wire goes to the coil and the purple wire goes to (assuming that your tractor has both the pto and the neutral safety switch) the pto safety switch first then back to the neutral safety switch then up to the solenoid. If you have 12v at the purple wire with the ignition switch in the start position and engine isn't turning the problem is some were else, not at the ignition switch. Also stick the test light on the small post on the solenoid with the key in the start position for 12v.