You know when you get in your truck, drive off, and then pull over real quick just to check if you locked the tailgate? That happened to me a lot (this is my first time owning a truck), so I decided to install a Power Tailgate Lock. The lock would be wired into the cabin door locks, so that it would function just like how SUVs have the dual-press option (press unlock once = only driver door gets unlocked, press unlock twice = all other doors/trunk unlock). I ran a pair of wires from the tailgate area to the left-rear passenger door lock harness. That took the most time since I loomed and wrapped the wires up first, and then ran them hidden along the frame rail. At the tailgate I installed a waterproof connector that piggybacked on top of the OEM backup camera connector. In fact, installing the actual door lock actuator was the easiest part.

Total install took about 45 minutes, and the cost of all parts came out to about $15 total. Now I know that whenever I lock the doors, the tailgate will definitely be locked as well.

Added a harness with a waterproof connector in case I need to remove the tailgate.
Here’s the new harness using the same access points as the OEM backup camera harness.
Drilled a small hole in the locking mechanism to attach the actuator rod.
This was the easy part – mounting the actual door lock actuator. Took all but 5 minutes tops.