Can I Add A Proximity / Motion Sensor?

I have an alarm system on my truck (installed by Best Buy). The components used in the install were: Compustar 4905S-KIT Firstech FT-ALARMIT-KIT (V2) Firstech FT-HRN-DC3 (High Current and Accessory Harness) Since that install a few years ago, I added a Drone X1 MAX module. I have installed a camper on my truck. Is there any way to install a motion sensor inside the camper, such that if there is any movement in the camper (a door or hatch is opened) the alarm is triggered? If yes, what part numbers or parts will I need to get? The camper is removed on occasion, so ideally I could put a quick connect where the wire enters the camper. Would disconnecting that wire cause some kind of fault or problem in the alarm?

You may want to consider using a PIR motion sensor. The sensor can feed into a negative trigger input on the alarm (like the trunk trigger input). Disconnecting the trailer and sensor will not cause any alarm faults. I've installed Ademco PIR motion sensors on RV's in the past and they worked extremely well. I think Ademco may have been purchased by Honeywell since then.