NighTvision and ThermaLvision problem

[Diamond King]

NighTvision and ThermaLvision just dont work me, no matter what I do
In sniper rifle scope zoom, i toggle them , screen flashes for a split second, then it reverts back to normal
I even installed mods that toggle NighTvision and ThermaLvision but same thing happens
i just cant get NighTvision and ThermaLvision to work
help somebody ?

[Reacon]

try it in a trainer