how to fix fl studio mod wheel
Another fast tutorial that respects your time. Hope it helps.
Most VSTs respond to CC1 coming from a keyboard automatically. But when FL stops routing this for some reason, you can reactivate it by opening Fruity Wrapper under installed-generators. Then current project-generators will have the Fruity Wrapper listed. Open that and all CCs are available. A right click on Modwheel CC1 will let you link to controller. Omni should be checked, so that CC1 will work on each invidual channel you select, not every channel all at the same time. I don't check remove conflicts, personally.
This is NOT a tutorial on linking CC1 to various VSTs by using midi learn or by using last tweaked etc.