My Z3 has a strange central locking issue that I need to look in to. When I use the key in either the passenger or drivers door it will operate the central locking for the doors. The boot does not lock or unlock if the key is used from the doors. If I use the key in the boot lid to unlock / lock the boot it also operates the doors. So, if I use the key in the door to unlock the door, both doors unlock but not the boot. If I lock the door from the door, both doors lock but not the boot. If I unlock the boot using the key in the boot, the boot will unlock and both doors will unlock. If I lock the boot from the boot lock, the boot will lock and both doors will lock. So, if I unlock the car from the boot and then lock the car from the doors, the boot will not be locked.
It appears that the signal from the central locking from the doors is not making it to the boot actuator. There is a known issue on the Z3 where the wiring loom that goes from the boot in to the car can sometimes contain broken cables. It could be that there is a broken cable in the loom. You can see examples of broken wires in the photos below (courtesy of @jonco on zroadster.org). Detailed below are the indvidual wires and there function.
As soon as lock down allows I will be out to the car to break open the wiring loom to see if any of my wires are broken and causing my issue. I will update the post with what I find.
I have documented here the details of what each wire is used for is noted below (courtesy of @jonco and @BrianH on zroadster.org)
There are 9 wires in the boot loom. The lock/unlock and switch position functions are controlled via the central ZKE module
The two wires below are part of a common loom that triggers the door actuator/lock.
1.5 BL/GR blue/grey – boot lock motor wire
1.5 WS white – boot lock motor wire
The three wires below are supply wires and lock position wires, the supply is fed from fuse 7 (5amp)
0.35 RT/GN red/green – boot lock switch – supply wire
0.5 WS/BL white/blue – boot lock switch – unlock wire
0.5 WS/GN/GE white/green/yellow – boot lock switch – lock wire
The two wires below are for the third brake light, the fuse for the third brake light is fuse F46 (15A) and controlled via the brake light switch.
0.5 BR brown – 3rd brake light – earth
0.75 BL/RT blue/red – 3rd brake light – supply Wire
The two wires below are for the boot interior light, this switch is located in the boot latch. The fuse for the boot light switch is F33 (10a).
0.5 BR/WS brown/white – boot light switch supply wire
UPDATE: I finally got around to opening up the loom and found that I had a blue wire that was broken. I stripped back the wire and soldered it back together and now the central locking works exactly as it is supposed to.