DIY: Unlocking problem, fixing the GM5 unit

So I have been unlocking problems with the 318 for the past year, where it wouldn't unlock in cold or hot conditions and got worse by the months went by and upon research it turned out to be the GM5 unit.

What you will need

1. Soldering iron
2. Desoldering iron and/or Desoldering wick
3. Solder
4. 2 x Siemens or Tyco (TE) V23084-C2001-A303
5. Multimeter
   

Other alternative relays are
V23084-C2001-A403 (255Ω ±10% coil, AgSnO₂ contacts)
V23084-C2002-A303 (178Ω ±10% coil, AgNi0.15 contacts)
V23084-C2002-A403 (178Ω ±10% coil, AgSnO₂ contacts)



Now here is what you need to do

Firstly you will need to remove the GM5 unit, it's located at the back of the glove compartment and takes approximately 25-30 minutes to remove.

After the glove box is removed you will see a white box with 3 connectors, remove them one by one. The tray the module sits in unhooks at the top, unhook it and the gm5 will slide out.




Now that it's out you need to take the PCB board, you will notice that there are pins holding the connector sockets in place, once these clips are pushed in the PCB will slide out of the casing from it's rail.

Here is where the fun starts, this is what the board looks like, notice the 2 relays with the writing "Siemens" on the left are the ones we are going to replace.





You will need to desolder the points below striked through with red line in the image below to be able to remove the relays


These are the new relays we will use


Once they are removed


Now solder the new relays back onto the board.


Now before we assemble we need to test that everything went according to plan, take your multimeter and test for continuity in the following locations, if you managed to break out anything then these are the soldering points as well.












Just reassemble everything as original.
After this you unlocking will feel like new, it will be responsive and reliable.