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.
You can determine the amount of current being used and charged on your tractor’s system by placing the meter in-series with the circuits of the tractor. To do this: first remove your red probe and plug it into the 10 amp Max port on your DMM. Then set your DMM to DC Current with the range of 10 amps. Now you unplug the wire going to your ignition switch’s “B” terminal. By clipping alligator clips to your DMM probes you can now connect one probe to the “B” terminal of your ignition switch, and your other DMM probe to the wire that normally goes to “B” terminal on the ignition switch. Now when you run your tractor the current will flow through the meter and your DMM can give you a reading. It will tell you how many amps are flowing through your system.