Let’s say you attempt to start your tractor and your starter does not engage. No click of the solenoid, nothing happens at all. Before assuming your starter is bad, grab your DMM and set it to DC Volts. Remove the wire going to the small terminal of your starter solenoid and connect the red probe of your DMM to the wire. Now connect your black probe to a ground. Turn your tractor’s key. Your DMM reads no voltage. This tells you that power is not going from your battery to the solenoid. Next remove the wires from the back of your ignition switch that are connected to the “B” and “S” terminals on your switch. Set your DMM to Continuity and connect your probes to the “B” and “S” terminals of the switch. Turn your tractor’s key and if there is no “beep” you know your ignition switch has a short internally and should be replaced.
We receive a lot of phone calls and emails from customers seeking help with their tractor issues. Some of the most common issues are related to the tractor’s wiring. It can be intimidating to look at a mess of different colored wires going in every direction, and try to make sense of it all. In this article, I will break down wiring theory and practices to its most simple and easy to understand form.
Most of the circuits in lawn and garden tractors use low amperage with the exception of the starting circuit. The wiring also only runs a short distance. I recommend using 6 AWG wire for the high amp starting circuit, and the negative side of the battery to common ground connection. All other wires can be 16 or 14 AWG. The easiest and most effective way to make all of the connections is by using nylon wire crimp connectors. Nylon wire crimp connectors are more durable than ones made from PVC. They are also easier to install than soldered connections. The most common crimp connectors you will use are spade and ring connectors.
Measuring resistance can indicate the health of a component. For example we can determine if an ignition coil is healthy or not by measuring the resistance of its windings. To measure resistance, set your meter to Ω ohms resistance. If you need to select a range, select the smallest range normally 200 ohms. Place the red probe onto one of the small terminals of the ignition coil, and the black one on the remaining small terminal. Your resistance will then display. A normal ignition coil should read about 3.5 to 4 ohms. If your meter reads a much higher resistance it means your ignition coil may have a short and is faulty.