The on-off switch in a string trimmer is occasionally called the kill switch. When this switch is in the “off” position, it is shut and running the electrical power in the spark plug to ground, that stops the engine. If the kill switch malfunctions, you could have trouble starting the trimmer or closing it off, based on what’s wrong. If it’s awful, you may need to pull the spark plug wire to stop the engine. It is possible to check the kill switch from studying its continuity, which you can do using a multimeter set to measure resistance in ohms. Allow the machine to cool before working on it to avoid injury.
Halt the trimmer and let it cool off. Pull the wire off the spark plug in case you didn’t need to do this to halt the trimmer.
Find the switch and also determine which part of the trimmer you need to disassemble to access the connections. If the switch is in the handle, you may need to separate the two halves of the plastic casing on the handle. If it’s about the engine casing, then you are probably going to have to remove a part of the casing. The process is usually straightforward, and you can do it using a screwdriver.
Set a multimeter to measure ohms, then set the results jointly and pick the scale that produces a reading of 0. Note that when the leads are apart, the reading is 1. These readings imply that the tiny current generated from the battery in the meter flows without any resistance once the leads are touching and resistance is endless when they are apart.
Disconnect the electrical leads from the switch and then touch the heads of the meter to the terminals. It is possible to touch either lead to terminal. Turn the switch to the “on” position; you should get a scan of 1 on the meter. If the reading is much lower than 1, then it indicates that the switch is partially shut, which is a flaw and means the switch requires replacing. In case you haven’t been able to get your trimmer to start, this is why.
Turn off the switch and check the meter it should read 0, which means that current is flowing through it. A high meter reading ensures that the contacts within the switch are faulty and that the switch needs replacing.