Hint button

Need help to find out why hint button doesn't work anymore.

Use the board on the gas tank near the purse on the road. When you fill the gas can your hint button will work again. That's the first time. check out some of the other threads here.

I'm viewing the first twin, I have a syringe and a blow torch and no hint button. have been back and tried using each of them on everything I can find. Nothing happens.
I need help desperately!