Why does my MDX hatchback lock not work?

cause and effects.
bingo

2008 Saturn Vue liftgate will not open

The endgate/liftgate can be locked or unlocked by operating either one of the front door lock switches, your's doesn't do this ?
Endgate/Liftgate
Once the vehicle doors have been unlocked, the endgate/liftgate can be opened by using the handle mounted to the exterior of the gate. The endgate/liftgate can be locked or unlocked by operating either one of the front door lock switches, or by pressing the Lock/Unlock button on the key fob. The endgate/liftgate lock and unlock functions operate in conjunction with the rear doors.

depends on your remote. Some have separate button for the trunk and some you press the unlock twice quickly.

It's inside the tailgate panel.Jump a 12v power supply to it and see if it works.It's quite simple to replace

Typical failure with the Nissan Versa,You need to find a auto electrician that is willing to go to the passenger side where the lock and unlock for the trunk module is located and and jump the wire together,This solves the problem forever, other than that the module needs to be replaced and yes you better make it a hobby it always fails

Trunk Lock After Closing
--------------------------
Desc.: What happens to the trunk lock when closing it.

Settings:
Yes: Automatically lock Boot on closing
No: Boot can be reopened using micro switch button located on the trunk/boot

* Trunk Lock After Drive Off
----------------------------
Desc.: Should the trunk be locked at drive off or after 30 sec.?

Settings:
Yes: Trunk/Boot will automatically lock when vehicle increases speed
No: Trunk/Boot will remain closed, however will be in the unlocked
condition if No was selected in the previous option.

* Door & Trunk Unlock at Key Out
--------------------------------
Desc.: When the is removed from the center console should door/trunk
be unlocked?

Settings:
Yes: All Doors & Trunk/Boot will Unlock when the Key is removed from
the Ignition Switch If Driver frequently locked all Doors when
driving
this feature would be beneficial.
No: Doors and Boot will remain in the same condition as they were
prior
to Key removal

* TSL Locking Logic (Theft Security Locking/Deadlock)
-------------------
Settings:
TSL at first Press: Default Setting. All Doors will lock in Deadlock
Mode
TSL at Second Press: All Doors will lock in Deadlock mode at the second
press of the Remote.

* Lock /Unlock Acknowledge
--------------------------
Settings:
None : No acknowledge will be visible
Indicators: Indicators will blink as acknowledge

* Follow Me Home Function
-------------------------
Settings:
Tail Light: When selected Tail Lights will be illuminated
Back Up Light: When Selected Reverse Light will be activated


Tech 2 Body Exterior Lighting & Horn
====================================

* High Beam Follow me home Active Time
--------------------------------------
Desc.: Follow Me Home Active Time can be adjusted between 0- 10 minutes

Settings:
This Feature can be turned on or Off .Yes / No can be selected.
Low Beam Automatic / Low Beam also in Position 0 (light switch)
Yes / No
Follow Me Home Active Time
- Daytime Driving Lights can be activated

* Parking Lights
----------------

Settings:
Act as Lead Me To the Car Light.

* Park Light On Reminder
------------------------
Settings:
On / Off
If Ignition is turned Off and the parking lights are active, Driver will
be warned if set to on.

* Show Trailer Light Outage
Desc.: REC will detect blown trailer light and display on SID

Settings:
Yes or No

* Trailer Light / Fog Light off
-------------------------------

Settings:
Yes: Fog Light Rear will be disabled When Trailer is connected Yes
No

* Horn Lock Unlock Acknowledge
------------------------------
Settings:
On: Horn will honk when car is locked
Off: Horn will not honk if car is locked


Tech 2 Body Locking
===================

* Panic Alarm Activation (Vehicles fitted with /Alarm only)
-----------------------------------------------------------
- Panic Button / Locking Switch
Central Locking Switch Driver /Passenger

Settings:
- Panic Button on Remote and locking switch inside vehicle will
activate alarm
- Panic Button will activate Alarm only
- Locking Switch inside vehicle (driver /passenger will activate
alarm only
- No Panic Alarm function required.

* Unlock Logic
--------------
Settings:
All at first press : All Doors will open & Fuel Lid will unlock if the
Driver or Passenger Door Switch is activated
Driver Door & Fuel Lid at first press : Only the drivers Door will unlock
& Fuel Lid will unlock when door
switch is activated

* Remote unlocking One Press
----------------------------
Settings:
All at first press: All Doors will open & Fuel Lid will unlock if the
Remote is pressed
Driver door & Fuel Lid at first press: Only the drivers Door will unlock &
Fuel Lid will unlock when the Remote
is pressed

you have to press it twice to unlock all doors or lock all doors.

drivers door latch is bad there is a module in the latch so the electric side is inop

check the clamp sensor front and back door

Flip the power lock switch on your dash (twice). Once only unlocks the drivers side door, twice unlocks the passenger side door and the hatchback. Good luck!