issue with 50.7x and want to add pin swit

add a pin switch to my tailgate.

I got the Clifford 50.7X installed at a local shop not too long ago.  Still getting use to it.  But I got a couple of "issues".  At the moment, I dont really trust the shop too much.  The seemed knowledgable when I was picking out my alarm.  But after the install, they were noobish.  Didnt know how to work the remote and stuff.  Also, the impact sensor wasnt sensitive enough.  Only on max setting could we get the warning chirp to go when you smack  the truck hard.  Had them relocate the brain and all was well with that.

Now I'm having issues with my remote start.  When I RS my truck, I get in and drive off, half the time, it doesnt automatically lock my doors.  I know all the doors are fully closed.  Also, 1 time, the RS timer did not shut off when I drove off.  I didnt have time to see what would happen when the timer got to 0.  Cant seem to duplicate that one.

The shop didnt want to install a pin switch for my tailgate.  They wanted to add another shock sensor back there....  I said no thx.  So how do I go about doing it myself?  Or should I choose a different option since the trigger would be exposed to water and nature.

got my pin switch... now just need to know how to set it up...

It's a toyota tacoma.  And no lights come on when I open the tailgate.