Why on ignition a buzzing sound with no start.?

A buzzing sound when you attempt to start your vehicle typically indicates an issue with the starter motor or the battery. If the battery is weak or failing, it may not provide enough power to engage the starter, resulting in a buzzing noise. Alternatively, a faulty starter solenoid may fail to make a proper connection, leading to the same outcome. It's advisable to check the battery voltage and connections, as well as the starter system components.