Our house has a home security system that was installed a number of years ago (guessing around the time the house was built in 2007, but not sure). The main panel is a PowerSeries PC1832.

All of the sensors are wireless except for the front door, which is a wired contact sensor. The end cap reads GRI 20RS-T, so I’m guessing it’s this:

GRI 20RS-T – 3/8 Press to Fit Switch – Alarm Grid

Recently this sensor has stopped recognizing whether the door is open or closed – it just always indicates that door is closed. If the alarm system is armed, opening the door does not trip anything. We’re using Alarm.com for monitoring, and their app also doesn’t see the door as ever opening (expected given the local system not registering it either).

I know nothing about how this is installed – all I can see is a 3/8 inch hole in the door frame with a small piece of metal sticking out after I remove the end cap.

Images: https://imgur.com/a/wIh952c

Is there a way to repair this without having to do major work on the door frame? What would be my first troubleshooting steps?