This info was for the 2000-2005 deville and is probably what you will need to follow.
As you know, the export model tail lamp does not work when plugged directly into a domestic model chassis wire harness connector.
Install 3 jumper or patch wires between the tail lamp connector and the chassis connector:
Jumper tail lamp connector pin C to chassis connector pin C (chassis ground)
Jumper tail lamp connector pin D to chassis connector pin D (lamp failure detection)
Jumper tail lamp connector pin E to chassis connector pin E (turn signal)
Two more sources of voltage to the tail lamp connector are needed. These voltages are available in the wire
harness that connects the trunk lid to the vehicle chassis. This wire harness is routed through the left side trunk
hinge arm and is available at the left rear corner of the trunk, behind the trim panel.
Open that harness and locate one WHITE wire and one YELLOW wire.
Use a Voltmeter and a sharp needle (to pierce the wire insulation) on the YELLOW wire to verify you have 12 Volts when
the BRAKE pedal is pressed. The YELLOW wire is the feed to the STOP lamp on the trunk lid. Splice into the YELLOW wire
and connect the spliced wire to pin B of the tail lamp connector.
Use a Voltmeter and a sharp needle (to pierce the wire insulation) on the WHITE wire to verify you have 12 Volts when
the headlamp switch is in the PARK LAMP position. The WHITE wire is the feed to the license lamps on the trunk lid.
Splice into that wire and connect the spliced wire to pin F of the tail lamp connector.
The final connections at the tail lamp six pin connector(s) will look like this:
Tail lamp connector pin A (not used)
Tail lamp connector pin B jumpered to trunk lid STOP lamp (stop lamp voltage from YELLOW wire)
Tail lamp connector pin C jumpered to chassis connector pin C (chassis ground)
Tail lamp connector pin D jumpered to chassis connector pin D (lamp failure detection)
Tail lamp connector pin E jumpered to chassis connector pin E (turn signal)
Tail lamp connector pin F jumpered to trunk lid license lamps (tail lamp voltage from WHITE wire)
Also here is a video showing the odd euro deville lamp in action