I used a serial but radio w/XM Satellite from a 2005 LeSabre in my '84 Caprice. I added the Keyless entry with the security system features shortly after. In that vehicle (and probably others), the Dash Interface Module (DIM) is the Power Mode Master. I also used the Instrument Panel Control Module, many times call the Body Control Module. You would also need the Driver's Door Module for an actual +12v/-12v to the door lock motor. I sent this signal to the OEM door lock relay in the car. I
did not set up the system as progressive, i.e. one remote button push for drivers door only, 2 pushes for all doors. You would also need Remote Keyless Entry control module as the antenna for the system. It also is matched to the remotes. Some GMs of this era cannot be programmed for new remotes without a Tech 2 type scan tool. Taking this module with already matched remote(s) is the way around this.
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I also had to use the Rear Interface Module to use the trunk release function for the car.
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The remote receiver is just a little module.
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