Location of tailgate open/close sensor

Anyone know how to access the tailgate sensor? Mine needs adjustment, occasionally the truck thinks the tailgate is open (when it isn't).

 

Bump. Having the same issue after installing a Retrax cover.

 

Just a follow-up to my original post: This problem was resolved by adjusting the tailgate latch so as to hold the tailgate closed more securely. In my case it was the latch on the right side of the tailgate, just loosen the bolts , slide the latch and tighten it down.

 

what size torx is that?

 

T-40