Where can I locate the front seat door panels that are in the back?

It is located behind the right rear quarter panel , In the back right of the interior !
Remove the right rear quarter trim panel. Refer to Rear Quarter Trim Panel Replacement - Right Side in Interior Trim.
Removal Procedure

1. Remove the rear seat. Refer to Rear Number 2 Seat Replacement or Rear Number 2 50-50 Seat Replacement in Seats.
2. Remove the Third Pillar trim panel. Refer to Third Pillar Trim Replacement .
3. Remove the garnish molding. Refer to Body Rear Corner Garnish Molding Replacement .
4. Remove the door sill plate. Refer to Liftgate Door Sill Plate Replacement .
5. Remove the quarter panel trim screws.

A lot involved in this but not to difficult !

1. Remove the rear door sill trim plate. Refer to Front Side Door Sill Plate Replacement or to Rear Side Door Sill Plate Replacement .
2. Remove the lower rear seat belt cover and bolt.
3. Remove the trim panel from the vehicle.

Remove the sill plate. Firmly pull the sill plate up and out from the retainers.
Remove the sill plate from the vehicle. Start from the front of the door sill. Use a flat-bladed tool in order to pry the door sill plate.
Rear Side Door Sill Trim Plate Replacement
Use a flat-bladed tool in order to pry the door sill plate. Remove the sill plate from the vehicle.
Body Rear Corner Garnish Molding Replacement
Remove the rear upper garnish molding. Refer to Rear Upper Garnish Molding Replacement .
Pull down on the upper corners of the garnish molding in order to disengage the retaining clips. Pull in order to disengage the remaining retaining clips. Remove the rear corner garnish molding from the vehicle. Inspect the rear corner garnish molding for broken or missing retaining clips. Replace the retaining clips as needed.
Good Luck ! Fun job !!!!!

slide the seat all the way forward , this should reveal the bolts at the rear ,once removed slide seat all the way back then undo the front bolts

do you have a second fob try it battery may be low may need reprogramed or replaced check with your dealer

from autozone.com:

Removal & Installation

1. Disconnect and isolate the negative battery cable.
2. Remove the right quarter trim panel as follows:
   1. Remove first rear seat. Remove the second rear seat, if equipped.
   2. Remove the sliding door sill plate.
   3. Remove the quarter trim bolster.
   4. Remove the upper C-pillar trim and D-pillar trim panel.
   5. Remove the first and second rear seat belt anchors.
   6. Remove the screws securing the quarter trim to quarter panel from the bolster area.
   7. Remove the screws securing the rear edge of the quarter trim to the support bracket.
   8. Carefully disengage the hidden clips securing the front of the quarter trim to the quarter panel just rearward of the sliding door opening.

   
   

Fig. Removing the trim panel to access the rear blower motor

i. Disconnect the wiring harness connector from the accessory power outlet, if equipped.

j. On long wheelbase wagons only, remove the quarter trim from the quarter panel and pull second rear seat belt through access hole.

k. Pull first rear seat belt through the access hole.

l. Remove the quarter trim panel from the vehicle.

3. Remove the 5 screws mounting the A/C-heater blower motor housing to the rear HVAC unit (one mounting screw located on evaporator cover).

4. Twist the blower motor out of scroll housing.

5. Disconnect the blower motor wiring connector.

6. Remove the blower motor from vehicle.


Fig. The rear blower motor is held in place by four screws
To install:

1. Install the blower motor unit into the vehicle.
2. Reconnect the blower motor wiring connector.
3. Secure the blower motor into scroll housing.
4. Install and tighten the 5 screws mounting the A/C-heater blower motor housing to the rear HVAC unit (one mounting screw located on evaporator cover).
5. Install the right quarter trim panel as follows:
   1. Install the quarter trim panel in position in the vehicle.
   2. Insert and pull the first rear seat belt through the access hole in quarter trim panel.
   3. On long wheelbase wagons only, insert and pull the second rear seat belt through access hole in quarter trim panel.
   4. Reconnect the wiring harness connector to the accessory power outlet, if equipped.
   5. Engage the hidden clips to secure the front of quarter trim to quarter panel rearward of sliding door opening.
   6. Install the retaining screws that secure the rear edge of quarter trim to support bracket.
   7. Install the retaining screws that secure the quarter trim to the quarter panel in bolster area.
   8. Install the second rear seat belt anchor (if equipped), and the first rear seat belt anchor.
   9. Install the D-pillar trim panel and upper C-pillar trim.
   10. Install the quarter trim bolster.
   11. Install the sliding door sill plate.
   12. Install the second rear seat, if equipped, and install the first rear seat.
       
6. Reconnect the negative battery cable. Check blower motor operation.

Front Door Panel - Town Car - Removal
CAUTION: To avoid breakage of door pull cover(s), insert a screwdriver diagonally between pull strap and chrome bracket. Snap out both sides then remove.

Snap out two door pull strap retaining screw covers. Remove screws.

Remove two screws on front and rear side of front door trim panel.
The following procedure must be used during removal and installation of the door armrest and trim panel. Refer to the appropriate illustrations for component and vehicle model identification.
Using the Trim Pad Removing Tool from Rotunda Windshield and Moulding/Trim Removal Kit 107-R0401 or equivalent, pry the trim panel retaining clips from the door inner panel.

NOTE: Do not use front door trim panel (23942) to remove trim clips from door inner panel. Replace any bent, damaged or missing push pins.

Remove window regulator control switch housing from back of front door trim panel . Lift up housing, remove retaining screws and disconnect all connectors.

Disconnect driver seat regulator control processor switch (driver door only) if equipped.
Twist out interior lamp wire assembly and remove the front door trim panel.
Installation

Ensure plastic watershield is secured to door panel.
Position front door trim panel to door. Connect interior lamp wiring.
Position the window regulator control switch housing and connect switch connectors. Install the retaining screws.
Connect driver seat regulator control processor (14C708) (driver door only) if equipped.
Align door lock side to its mating slide on the sheet metal (front doors only).
Snap in front door trim panel. Ensure all retainers fit properly.
Install two retaining screws on front and rear side of front door trim panel .
Install two retaining screws and pull strap covers.

Good luck Remember rated this).

dealer or junk yard

remove trim panel, remove mirror fasteners.

Glass, Outside Mirror—Town Car

Removal and Installation

1. Push upper edge of outside rear view mirror glass (17K707) into the outside rear view mirror to expose latch release.
   

1. Using a small flat-bladed screw driver or equivalent, move latch release to released position.
   

1. Remove outside rear view mirror glass mounting back and outside rear view mirror glass from outside rear view mirror.
   

1. Disconnect heater wire connectors and auto dimmer connector, if equipped.
   

1. To install reverse Removal procedure.
   

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Mirror, Power—Outside Rear View
Town Car

Removal and Installation

1. Disconnect battery ground cable (14301). Refer to Section 14-01 .
   

1. Remove front door trim panel (23942). Refer to Section 01-05 .
   

Trim Panels, Door Front—Town Car
Removal

1. Snap out two door pull strap retaining screw covers. Remove screws.
   

1. Remove three screws on front and rear side and center of front door trim panel (23942).
   

1. NOTE: The following procedure must be used during removal and installation of the door armrest and trim panel. Refer to the appropriate illustrations for component and vehicle model identification.
   
   Using the Trim Pad Removing Tool from Rotunda Windshield and Moulding/Trim Removal Kit 107-R0401 or equivalent, pry the trim panel retaining clips from the door inner panel.
   

1. NOTE: Do not use front door trim panel to remove trim clips from door inner panel. Replace any bent, damaged or missing push pins.
   
   Remove window regulator control switch housing from front door trim panel. Lift up housing in front and disconnect all connectors.
   

1. Disconnect wiring harness and heated seat switch electrical connectors if equipped.
   

1. Remove the door trim panel.
   

1. Disconnect two electrical connectors.
   

1. Remove nut from outside rear view mirror mounting base.
   

1. Swing outside rear view mirror (17682) toward driver door window glass to expose screw in mount base.
   

1. Remove screw from outside rear view mirror base.
   

1. Remove outside rear view mirror from front door (20124). Guide wiring and connectors through hole in front door.
   

1. To install, reverse Removal procedure. Tighten nuts to 8-10 Nm (71-88 lb-
   

Motor

1. Disconnect the negative battery cable.
   
2. Remove the door trim panel and watershield.
   
3. Detach the motor wires at the multiple connector.
   
4. Remove the motor retaining screws using Torx® drive bit set D79P–2100–T or equivalent, and separate the motor from the bracket and cable drum housing.
   
5. Remove the motor from inside the door.
   

To install:

1. Position the motor and drive to the cable drum housing and motor mounting bracket. Install the 3 motor screws and tighten.
   
2. Connect the power window motor wiring.
   
3. Connect the negative battery cable.
   
4. Check window operation.
   
5. Install the watershield and door trim panel.
   

Door Panel

1. Disconnect the negative battery cable.
   
2. Snap out the two door pull strap retaining screw covers. Remove the screws.
   

CAUTION To avoid breakage of the door pull covers, insert a small screwdriver diagonally between the pull strap and chrome bracket. Snap out both sides then remove.

1. Remove the two screws on the front and rear side of the front door trim panel.
   
2. Using the trim pad removing tool, pry the trim panel retaining clips from the door inner panel.
   

NOTE Do not use the front door trim panel to remove the trim clips from the door inner panel. Replace any bent, damaged or missing push pins.

1. Remove the window regulator switch housing from the back of the front door trim panel. Lift up the housing and disconnect all connectors from the switch housing.
   
2. Disconnect the driver seat regulator control processor switch if equipped.
   
3. Twist out the interior lamp wire assembly.
   

To install:

1. Ensure that the plastic watershield is secured to the door .
   
2. Position the front door trim panel to the door. Connect the interior lamp wiring.
   
3. Align door lock side to its mating slide on the sheet metal.
   
4. Snap in the front door trim panel. Ensure all retainers fit properly. Install the two retaining screws on the front and rear side of the front door trim panel.
   
5. Connect the driver seat regulator control processor, if equipped.
   
6. Position the window regulator control switch housing and connect the switch connectors. Install it to the front door trim panel by snapping it in, or by installing the screw at the rear.
   
7. Install the two retaining screws and pull strap covers.
   
8. Connect the negative battery cable.
   

As I remember, you need to remove the front seat belt mount, & completely remove the back seats, in order to remove the rear door cards, without breaking them.
Have fun;)