Welcome to the site !!
I am guessing you washed the bike and got the switch wet and it shorted out ... usually the cause ... and yes that is a common issue ...
Only solution is to replace it as it is internally shorted , most likely if water was the cause ...
Avoid ..... washing the kill switch , I usually wrap a 1 gallon Zip-Lok bag over the end of the grip/bar , to cover it and use a long garbage bag tie to seal it off , then wash away , ... I also just wash everything else and leave that part and wash it by hand with a toothbrush and some cleaner , and I ALWAYS blow the switches off with air before attempting to start the bike , as that is when it will short out , is when you crank it and the circuit board is wet ... but yea , a dirt bike you can't get wet

..... all the electronics make the bike better , but make everything else worse ...like washing the bike ..