1997 cadillac Deville D'Elegence

Yes it could be the reason for the parasitic drain. Do a parasitic drain test and see what the amps or milliamperes are on the system. Then if higher than 50 milliamperes pull the fuse for that trunk motor and see if amps drop down in acceptable range

Sometimes it is the switches that tell the motor to start and stop. There are two that are connected to the motor and latch pieces, upper and lower. Switches are cheaper than a new motor and they do go bad which would potentially keep the motor running and draining your battery.

How do I disconnect the trunk motor

You will need to take some trim off that surrounds the motor and then remove the hardware holding the motor and switch in place. You will also need to unplug the electrical connection at the motor/switch.