I have just recently purchased foza 7, i was going to start and play with my thrustmaster TMX wheel, but for some reason, i couldnt use my wheel for forza 7, it wouldnt even show up in the controller settings in game. I have used this wheel for other games and it works
I have checked forza 7 does support Thrustmaster TMX, but some how it just wouldnt work, it isnt able to do anything in the game but i can still control my xbox eith the wheel.
Does anyone have any issue with this?
Regards,
Seems like a similar problem to my Ferrari 458 Spider wheel. Try my solution for this wheel, maybe it will work with your controller too.
Start FM7 using steering wheel and wait for the main menu. Then go to Xbox dashboard, logout from your Xbox account and login again. After that game will be restarting. Close FM7 and then start the game again. Do everything using buttons on steering wheel. It works for me, maybe it will work for you too 
After turning your Xbox on and booting up, turn off your controller, then use the wheel to load FM7.