boot and petrol flap locks have gone awol.

[povertyspec]

i have had several past run ins with central ocking systems. before i go on special ops trip into the trim of my wives 1988 320i is there a possible simple solution to why the boot and petrol flap are no longer on the central locking team. the boot happily accepts the key on manual opening and will lock from the drivers door but doesnt want to unlock. is the boot through any junction boxes, if it was lube why does it lock ok??.