keeps blowing fuses

What does the legend say the fuses do?

7 and 34 control the central locking and the problem could be in the actuators or the wiring going to the actuators or the general module that controls the central locking.

i checked the rear tail lights and they was bad and sockets were white and dirty.also there is a small black box in with fuses that makes noise when we replace fuse then it blows again.this will not let me start car at all.still not sure where to look.and does anyone have a wiring diagram for 1996 z3?

Amazon.com for a Bentley repair manual.

I know this is an old post but, the problem is probably in the wires in the trunk. Check the wires on the trunk lid going to the lock solenoid ( they tend to get crushed by the hinges and break). Also the solenoid for the gas cover locks will sometimes seize and create a load on the circuit causing the fuse #7 to blow there-by cutting power to the immobilizer control module and the anti-theft module.