Hi.
None of the buttons one the steering wheel are working along with the left paddle shifter on my G27. This is not an LFS only thing, The g27 driver doesn't pick up inputs from any button on the steering wheel.
However the pedals, H pattern shifter and buttons on the shifter all work fine along with all the shift lights. Which leads me on to think that the problem is in the pcb behind the steering wheel where the shifter paddles are.

Does anyone know why this is happening and if it is fixable or not?

Thankyou.

All the buttons, LEDs and rotary encoders on the wheel rim of most wheels and also in G series Logitech wheels are first connected to the electronics on the small PCB, just underneath the plastic. Those signals are then serialized by the use of shift register chips. Usually, each can handle up to 8 buttons, or 8bit shifts. Connecting those chips in series makes it possible to have many more buttons. This PCB is connected to the main PCB in the wheelbase by usually no more than a 6 wire cable (SPI). On both PCBs they put cheap small connectors. The cable needs to be twisted in a coil or spring to allow the wheel rim rotation without tearing it.

Now, your problem may be in any of those points. I would say this is the most probable failure order: cable came loose on the connector in wheel rim PCB, some of the wires got damaged, or a dead shift register chip. These are the points where you might find a problem and fix it. The problem might even be on the main PCB itself. If so, unfortunately, nothing can be done.

G27 has 6 buttons, 2 paddle shifters and 5 LEDs (10 total). Not exactly sure how they wired the shift registers, I never opened it. At least on G29 wheel rim they have 3 of these chips. You say 1 paddle shifter is still working. Did the other buttons just stop working all at once?

Thankyou for the answer, looks like I will have to get the soldering iron out and dig a bit deeper than I was hoping.

No problem man, I hope that it is just a loose connector. This is common for old and rumbly devices.

Let's hope so