Coolster ATV Electrical Problem
 

My son was riding his Coolster 125 yesterday and it randomly died on him mid ride. Now the starter button doesn't work. Every now and then I will hear a single click when pushing the starter button, but that's it. Battery is good, brake lights turn on. Thanks for your help.

how did you check the battery? how old is the battery? If these little battery's are not kept on a maintainer they are junk in a year or so as the system can barley keep up with charging

Check battery connections and those on solenoid. If the battery is OK, either the starter or solenoid has gone wrong. To test, get a 12v test lamp, one wire onto battery neg, the other onto the solenoid wire going to starter motor, switch on, press starter, if lamp lights but starter doesn't turn, faulty starter, if solenoid clicks but lamp doesn't light, faulty solenoid. Other possibility if lamp lights is bad earth, so move the neg wire of the test lamp onto a good earth point on the engine cases and test again, if lamp doesn't light this time bad earth. Of course he may have seized the engine...