This is not my strong point BUT maybe try trouble shooting a few things.
1. If you lift the deck lid slightly does it then open?
2. How is your battery? If your battery is weak it could affect the deck lid going up. Also depends if you use a generator or alternator. I would make sure everything is fully charged.
3. If when you get the deck lid open will it close and lock correctly or does it sit there and the screws spin (or not spin at all)?
4. If the deck lid has worked in the past then I would try my steps before anything else.

Like the other post said it could be the position B switch but I would try what I said before you start moving the switch a little. It can be tough to find that sweet spot once you get it.
Good luck