Before using your DMM plug the two probes into their appropriate places on the meter. The black probe will plug into the common port labeled “COM.” The red probe will plug into the “VΩµmA” port for most testing.
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.
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.
Think of this as electrical volume. Amps can be determined by taking your voltage (12 volts) and dividing it by the resistance of a load. This is illustrated with the following formula: A = V/R