bmw x5 2005 e53 lower tailgate wont open

[maci234]

when i press button to open lower tailgate i get a noise  but still wont open tailgate does,nt seem as if there is enough power in it , already changed actuator from original and its the same , when i open lower tailgate manually and lay it down flat , i manually lock each lock on each side then press the button and they both unlock ,of course there is no pressure on them when in the open position ,anyone have any idea what it could be  thanks in advance