2000 explorer not starting

[rooney]

hi all
have a 2000 explorer, when I try to start,sounds like the starter solenoid chattering and nothing from starter. when jumped from another vehicle, starts right up. any help much appreciated.
thanks

 

[my98nnj]

Battery is toast.

 

[Chikar]

If it starts right up from a boost we can assume the starter, and starter solenoid are OK.

My thought would be you have a bad battery. Or maybe just really dirty battery posts?