This guide will also be good for face lift cars as well since the module is more easily accessible again behind the glove box.
Example guide https://www.bmwgm5.com/GM5_Z4_Removal.htm
On my pre-facelift car the linked instructions are mostly correct except that the module is on an alloy bracket right up behind the glove box/fuse panel and requires a stint upside down in the footwell with your head jammed on the floor to see what you are after. (It would be an advantage to be about 4'6" tall, skinny and have fingers like ET! )
- Removing the complete glove box will not help and isn't necessary.
- Once you have undone the two screws on the panel under the glovebox the panel drops down, you will need to unplug the lamp cable to get the panel out of the way.
- Then it's best to first remove the two plastic nuts (10mm not 8mm as stated in the link) holding the white GM5 module bracket to the bulkhead, a small 10mm ratchet does the job
- Then drop the module down on it's bracket and remove the 3 wiring block plugs. Unfortunately you can't really see how to unhitch them so it's worth closely noting the two pictures (sourced from the bmwgm5.com link) or you will get very frustrated!
The all-black right block has an outer case that slides diagonally to the right right with the help of a flat screwdriver blade gently prising it sideways from the top (down the side of the wires) it's very sticky but just keep gently prising it right and it will come off.
On the other two plugs with white plastic securing clips you simply need to press down the central black tab on the top next to the white clip, then swing the clip open. All 3 plugs take seconds when you know how, or ages (upside down) when you don't, and cant see!
The modules are coded to the car so you can't simply drop one in from BMW or a scrapper, my module will be sent off for repair next week, hopefully this will sort the problem (about £35 instead of £400+ from BMW!)