Are the keys in the ignition? If so all you have to do is take them out when you open the door.
Your battery is dead.
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Open the glove box and let the squirrel out!!
cicadas
Both bees and mosquitoes make the buzzing noises with their wings. Their wings are moving at such a high rate of speed that it makes the vibrations and buzzing sounds.
Because their wings move so fast that it creates a buzzing noise
That is the electric fuel pump that's inside of the fuel tank. That is a common problem with the Chevy trucks. A dirty fuel filter will cause the pump to make that noise or the fuel pump is wearing out.
Replace door moulding
yes, the fan bearing is worn out
Well, this is certainly among the strangest questions I've seen here. Is the buzzing from the headlight it's self, or is the noise inside the cabin?
Sorry forget to mention it in the motor.
The fuel pump coming on. Most cars prime the pump when you turn the key on, but VW does it when you open the door.