central locking

hi guy ,hope somebody can help here,first my back door wasn't locking which in turn was immobilising the car,disconected back door,alarm still going off saying drivers front door, or sometimes front passengers door but mostly drivers side,took lock apart and cleaned it, alarm still going off,then i got new lock still didn'twork,i think its all to do with backdoor not closing,i've changed boot lock ,solinoid,button,still no joy,its doing my ****in nut in,i hope somebody can help cheers pat.