The Rear Left Door Lock Will not unlock with the remote button or the in car switch

Sorry Andrew , no BCM on this vehicle . The Central Security Module is incharge of power door locks . Central Security Module For additional information, refer to Section 419-10 .
The central security module is equipped with a battery back-up which holds the programmed transmitter(s) memory in the event of the vehicle battery disconnection.
Principles of Operations The Door Switch Lock Function When a door lock switch is moved into the lock position or a door lock cylinder is rotated to the lock position, the door lock switch grounds the lock circuit input to the central security module. The central security module then provides 12 volts to one side of the door lock actuators contained in the door latch unit and simultaneously grounds the other side of the door lock actuators. This completes the door lock actuator circuit, causing the door lock actuators to rotate a cam assembly, which then locks the doors.

The Door Switch Unlock Function When a door lock switch is moved into the unlock position, the door lock switch grounds the unlock circuit input to the central security module. The central security module then provides 12 volts to the opposite side (relative to locking the door) of the door lock actuator(s) contained in the door latch unit and simultaneously grounds the other side of the door lock actuator(s). This completes the door lock actuator circuit, causing the door lock actuator(s) to rotate a cam assembly in the opposite direction, which then unlocks the door(s). The 12 volts which the central security module provides to the door lock actuator(s) are provided to each door lock actuator from the individual pins on the central security module connector.

Keyless Entry When a remote transmitter button is depressed, it transmits the appropriate command to the central security module as a radio frequency. The central security module receives the command from the remote transmitter through an antenna, which is incorporated in the central security module.
When the central security module receives a command from the remote transmitter, it then sends the appropriate output to control the desired devices. These outputs devices include:

• The front and rear door lock units.
• Central timer module (CTM).
• The liftgate release motor.
• The right and left side turn signal lamp(s).

The central security module sends a signal to the CTM when courtesy lamp illumination is required.
Computer Operated Locks Each front door lock actuator contains a bipolar motor that controls the lock and unlock linkage. The lock/unlock lever of both front door interior handles use linkage to actuate the lever lock switch located inside each front door lock actuator. Each lever lock switch remains in the unlock position until lock/unlock lever of the interior door handle is moved to the lock position. This action toggles the lever lock switch to the lock position. The central security module uses only one electrical input for both lever lock switches. The central security module cannot determine whether the driver or passenger door lever lock switch was actuated. Therefore, actuating the lock feature from either front door will have the same affect of locking all doors. Actuating the unlock feature will not unlock any other door.
The door lock control switches for both front doors also use only one input to the central security module.
Both rear passenger doors contain a rear door lock actuator that controls only electric lock or unlock of the door. Actuating the lock/unlock lever at either rear passenger door will have no effect on other doors.
The panic feature of the remote transmitter sounds the vehicle horn when the vehicle is not equipped with anti-theft. If the vehicle is equipped with anti-theft feature, a separate horn is sounds for the panic feature.

Power Door Lock Operation
The vehicle is equipped with power door locks. Each lock actuator is powered and controlled by the door module mounted in the individual door, but the rear integration module (RIM), which is the master control for the door lock system, determines when the lock functions are permitted. The RIM receives and examines the requested lock function from the individual door modules, or from the remote function actuator (RFA) via the class 2 serial data circuit. The RIM also examines the transmission shift selector position and the ignition switch position information available over the Class 2 serial data circuits. If the RIM determines that a lock or unlock function is permitted, it sends a class 2 message back to the individual door modules commanding them to perform that Lock or Unlock function.
Power Door Lock Components
The power door lock system consists of the following components:
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Driver door lock switch

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Passenger front door lock switch

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LH rear door lock switch

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RH rear door lock switch

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LH middle door lock switch (w/ V4U)

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RH middle door lock switch (w/ V4U)

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Driver door switch assembly (DDSA)

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Driver door module (DDM)

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Passenger front door module (PDM)

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LH rear door module (LRDM)

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RH rear door module (RRDM)

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Left middle door module (LMDM) (w/ V4U)

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Right middle door module (RMDM) (w/ V4U)

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Driver door lock actuator

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Passenger front door lock actuator

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LH rear door lock actuator

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RH rear door lock actuator

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LH middle door lock actuator (w/V4U)

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RH middle door lock actuator (w/ V4U)

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Driver door cylinder unlock switch

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Rear integration module (RIM)

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DRVMDL fuse (10-amp)

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PASS MDL fuse (10-amp)

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RRDR MDL fuse (10-amp)

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Class 2 serial data link

Will that door unlock from the master switch at the drivers door or the rear left doors own switch ?

Lock/unlock motor may be failing. Remove the door panel and remove the connector from the lock motor. Check the dc voltage at the connector while pressing the lock switch. If you see battery voltage, replace the motor. If the voltage is low, inspect the wiring.

Do any of the other buttons on the remote work, like the horn or trunk-open buttons? If they do, then you might have a blown fuse or relay switch for the specific problem. On my Grand Am, there are relays for "Door Lock", "Door Unlock" and "Driver Door Unlock".

Sounds like your door module is the issue. You can try to disconnect the battery for 5-10 minutes then retry or GMC to see if there is a recall.

The most likely cause is a defective lock actuator.You'll have to pull the door panel to get at it.Unplug the connector,and rig a 12v test light across the two connector pins.Pressing the lock or unlock button should make the light come on(lock or unlock just reverses the polarity).If you get a light,then the actuator is the problem.If not,then trace back towards the lock relay to find the open in the circuit.

Battery Constant 12v+ Positive Wire (+): Black/Yellow
Battery Constant 12v+ Positive Wire Location: Ignition Switch Harness

Starter Positive Wire (+): Blue/Red
Starter Positive Wire Location: Ignition Switch Harness

Ignition Positive Wire (+): Red
Ignition Positive Wire Location: Ignition Switch Harness

Accessory Positive Wire (+): Red/Yellow
Accessory Positive Wire Location: Ignition Switch Harness

Parking Light Positive Wire (+): Red
Parking Light Positive Wire Location: Low In Drivers Kick Panel

Power Door Lock Negative Wire (-): Add Actuator. This vehicle uses a central door locking system. When connecting a keyless entry, you will need to add a door lock actuator and some units will also require (2) extra relays.
Power Door Lock Negative Wire Location: To Drivers Door Only

Power Door Unlock Negative Wire (-): Add Actuator. This vehicle uses a central door locking system. When connecting a keyless entry, you will need to add a door lock actuator and some units will also require (2) extra relays.
Power Door Unlock Negative Wire Location: To Drivers Door Only

Door Trigger Negative Wire (-): Red/White
Door Trigger Negative Wire Location: In Black Plug, Above Hood Release

Domelight Supervision Wire: Use Door Trigger, Requires Relay
Domelight Supervision Wire Location: N/A

Horn Negative Wire (-): Red/Green
Horn Negative Wire Location: At Steering Column Harness

Tachometer Wire Negative Wire (-): Black/Blue
Tachometer Wire Negative Wire Location: At ECM, Under Drivers Side Dash

Brake Light Positive Wire (+): White/Black
Brake Light Positive Wire Location: At Switch Above Brake Pedal

CODE ALARM SYSTEM

Used on:
Impreza 1996-2001
Legacy 1995-1999
Forester 1998-2000

Battery GP-23A

Lock: Left button will lock all doors. Double chirp indicates locked.
Unlock: Right button will unlock driver's door only. Hold unlock button app 6 seconds, it will unlock all doors including rear gate. Single chirp indicated unlock.
If the car chirps or lights flash 4x the alarm was triggered.
Panic. Press both buttons to activate emergency honk and flashing lights.
Valet mode: With optional alarm onlyPress the red alarm button on the left of the steering wheel. The light will quickly double flash. To re-set back to normal mode, press the red alarm light button again

Battery failed and lights flashing?
Parking lights will flash when the vehicle's battery is disconnected and reconnected.
To stop lights from flashing, either:
Press remote transmitter "UNLOCK" button once OR turn the ignition switch to the "ON" position and press programming button for one second (see below).
The vehicle interior (courtesy) light and door open warning light (DOOR AJAR indicator) will then illuminate for 60 seconds when the ignition is turned off, or until the doors are locked with the remote transmitter. Yes, the dashboard instrument panel lights will flash when the parking lights flash.

Programming or Overriding the Alarm when you have lost the remote
Open driver's door.
Turn ignition key to 'On'
Press and *hold programming button* in (see diagram, button under dashboard)
After 15 seconds the the door locks will cycle 3 times. Do not release Programming button.
Press lock (left) button the remotes to be programmed. The door locks will cycle one time. Exit programming mode by releasing Programming button under dashboard and turning key to off.

Code Alarm Programming Button is under dashboard on the kick panel by the driver's left knee, left of the steering column. If you can't find it, it might still be tucked up in the wiring harness higher up in that same general area. The botton is recessed in a plastic ring (see diagram).
This button must be pressed while programming remotes or if the battery was disconnected and the lights are flashing.

it is probably your door lock has gone into safe mode.you need a new door lock.try using the lock/unlock button on your remote or on the drivers door button and gently tap the door handle with your hand while pressing the lock/unlock button,carefull not to dent your car.if that does not work,try disconnecting the cars battery for a few minutes,but note the vehicle might pick up fault codes which need a diagnostic machine to clear...good luck

child safety locks or bent linkage ?