I know nothing about the Force-EX but i'm guessing it's probably a dying button/microswitch. Most wheels are not that difficult to disassemble so it should be possible to replace/repair if you have basic soldering skills.
Part of my day job is sourcing/purchasing electronic components so if you can isolate the part i can probably find one for you.
Having said that, second hand one's can be found between £10 and £25 on eBay so it's barely worth the hassle. linky
Ideally you could always save up for Driving Force GT. Damn fine wheel for the cash.