Is it normal to have a whining noise coming from the back of the car? With the hazards or brake lights on it changes the noise. Its really strange, but I'm guessing its coming from the fuel pump. It seems to work fine, I'm just wondering if its gonna die soon, or if I should just ignore it?

 

Noise?? That's mustang Music!

 

mine does the same thing, its just changing rpm on the amperage that its getting, and when lights or another current draw is going on the pump gets less and slows the rpm a little and thus changes the frequency of the note

 

mine does the same thing