Rear entry doors will not open, recent problem. How to release to open, normal release does not work.

Do you have keyless entry ?
The remote keyless entry system performs the following functions:
• Locking the vehicle doors
• Unlocking the vehicle doors
• Opening the rear compartment lid

Rear Compartment Lid Release Circuit Description
The BCM receives a signal via Class II from the PCM indicating the position of the transaxle range switch. When you press the release button on the RKE transmitter, a signal is sent from the remote control door lock receiver through circuit 377 to the BCM. Then, the BCM sends a ground signal through circuit 253 to the rear compartment lid release relay. The relay receives power from the DOOR LOCKS fuse. When the relay receives the ground from the BCM, the relay's internal switch closes sending B+ (via circuit 56) to the rear compartment lid lock release actuator. A ground is always supplied to the actuator through circuit 350. When B+ is received at the actuator through circuit 56, the rear compartment lid releases.

You could jumper pins at the rear compartment lid release relay , this would open it .
Rear Compartment Lid Release Relay
Behind the IP compartment, attached to the underside of the cross-car beam . Need to pull glove box out .

NO FOBS DETECTED
Refer to Keyless Entry System Description and Operation

Keyless Entry System Description and Operation - Passive
Passive keyless entry allows entry to a locked vehicle without pressing any buttons on the keyless entry transmitter. You must only have the transmitter with you. This passive system is also part of the vehicle starting system. It allows you to start and run the vehicle having only the transmitter as your key. The passive entry and starting system use low frequency antennas in 4 different areas on the vehicle to determine the location of the transmitter. When passively opening a locked door or the rear compartment lid, you must have a programmed transmitter with you in your pocket, purse, or briefcase. As a customer opens the door handle or presses rear compartment touch pad, the low frequency antenna sends out a challenge to the keyless entry transmitter. The transmitter must be in a one meter range of the door or rear compartment lid in order to receive the challenge. If the challenge is met, the transmitter will respond, allowing the door to be unlocked and opened. Passive entry allows you to operate the following features:
• Passive door unlock/unlatch
• Passive rear compartment lid release
• Illuminated entry lamps
• Vehicle starting
The keyless entry system has the following components:
• Keyless entry transmitters
• LH and RH door antennas (part of the door handle assembly)
• Rear compartment antenna
• Console passive antenna
• Console active antenna
• Instrument Panel Module (IPM)
• Rear Integration Module (RIM)
• Remote Control Door Lock Receiver (RCDLR)
• External RF Antenna (includes coax from RCDLR to back glass)

Remote Control Door Lock Receiver (RCDLR)
The RCDLR is a multi-function module which controls all the vehicles antennas for passive keyless entry functions. The RCDLR also acts as the receiver for active keyless entry and tire pressure monitoring (TPM) functions, as well as controlling all immobilizer functions.
The RCDLR's RF antenna is located in the back glass, and there is a coax cable connecting the glass antenna to the module located in the trunk.

Your best bet , take it to a qualified repair shop that has the factory Tech 2 scan tool or someother professional type scanner that can read • Rear Integration Module (RIM) DTC'S - diagnostic trouble codes .

Voltage is applied at all times through the TRUNK REL/RFA fuse to the rear compartment lid release switch and the switch side of the rear compartment lid release relay. When the release switch is pressed, the following actions occur:
• The switch closes.
• Voltage is applied to the coil side of the rear compartment lid release relay.
When the transaxle is in PARK or NEUTRAL, the rear compartment lid release relay is grounded through the transaxle range switch. With the coil side of the relay energized, the relay contacts close, applying voltage to the rear compartment lid release motor.
If the vehicle is equipped with remote entry, the switch operation is the same, except when the contacts in the rear compartment lid release relay close, voltage is applied through the normally closed contacts of the remote control door lock receiver. This action occurs in order to apply voltage to the rear compartment lid release motor.

Can you check fuse's , relay ? Both are located in the left insturment panel fuse box . Fuse Block - Left I/P
On the left side of the I/P
you need to open the drivers door to get to it ,on very end of the insturment panel .
Do you know anything about relay's , how they work ? If you pull the relay out of the fuse box an look on the bottom you will see four set's of numbers . 30 & 87 . if you took a piece of wire an jumped were this pins plug into the fuse box the trunk would open . provided there is B+ voltage at pin 30 .
There are videos on youtube showing how to test relays and their circuits .

The rear compartment lid release system consists of the following components:
• Body control module (BCM)
• Folding top cover actuator
• GMLAN serial data link
• Keyless entry transmitter
• Rear compartment lid ajar switch
• Rear compartment lid release actuator
• Rear compartment lid release switch
• Remote control door lock receiver (RCDLR)
• Trunk fuses
• Trunk release relay

Rear Compartment Lid Release System Operation
The rear compartment lid can be released by operating the rear compartment lid release switch or pressing the rear compartment lid release button on the keyless entry transmitter. When the rear compartment lid release switch is operated, the rear compartment lid release switch signal circuit to the body control module (BCM) is switched to ground. The BCM receives the rear compartment lid release switch input and applies ground to the trunk release relay control circuit. This energizes the trunk release relay coil, closing the switch side contacts, allowing battery voltage to be applied to the rear compartment lid release actuator and folding top cover actuator, releasing the buttresses and opening the rear compartment lid. Ground for the rear compartment lid release switch is provided at G300. The rear compartment lid ajar switch, rear compartment lid release actuator, and folding top cover actuator are provided ground at G301. The rear compartment lid will not release until the vehicle speed is zero and in park.

Do you know what DTC'S - diagnostic trouble codes are ?
DTC B3265 01 : Trunk Relay Output Short to Battery
DTC B3265 06 : Trunk Relay Output Short to Ground or Open

Do you know what a relay is an how it works ? TRUNK release relay located in the underhood fuse / relay box.
VEHICLE RELAYS Operation Diagnosis

Your best bet would be to have the vehicle scanned for DTC'S - diagnostic trouble codes first . Do you know which of these your vehicle has ?
Keyless Entry System Inoperative (Active)
Keyless Entry System Inoperative (Passive)
Does the customer complain about other symptoms related to this, such as poor range when the key fob buttons are pressed or intermittent Tire Pressure Monitoring issues? (It's possible the RF External Antenna at the RCDLR may have a poor connection.)
YES - Go to Step 3
No - Go to Step 4
3
Inspect the external RF antenna connection at the RCDLR. First, gently pull on the coax connector at the module. If the coax comes out, then it wasn't seated properly. Remove and carefully inspect the coax connection for bent blades or a bent center pin. Fix coax connection if necessary and re-seat connector until a "click" is heard. Gently pull on the coax connection to make sure it is seated properly. Was the inspection made?

Press each button of the transmitter one at a time.
Does the system operate normally?
YES - Go to Testing for Intermittent Conditions and Poor Connections
NO - Go to Step 5
5
Lock and unlock the door locks using the controls inside the vehicle.
Do the locks operate properly?
YES - Go to Step 6
NO - Go to Symptoms - Doors

6
Operate the rear compartment release and the fuel door release from the controls inside the vehicle.
Do the rear compartment release and the fuel door release operate properly?
YES - Go to Step 7
NO - Go to Symptoms - Body Rear End

Important: Ensure that the keyless entry transmitter is the correct model for the vehicle remote system. A wrong model transmitter may pass this test, but will not activate the keyless entry system.
Turn on the J 43241 Keyless Entry Tester.
Place the transmitter on the J 43241 test pad.
Press each button of the transmitter one at a time.
Does a tone sound and the green light illuminate on the J 43241 after each button is pressed?
YES - Go to Step 12
NO - Go to Step 8
8
Do any of the buttons on the transmitter sound the tone and illuminate the green light when pressed?

11
Replace the keyless entry transmitter. Refer to Transmitter Programming.
Did you complete the replacement?
Go to Step 12
--
12
Perform the programming procedure. Refer to Transmitter Programming.
Did the drivers information center (DIC) beep and display a message ready for next fob?
Go to Step 14
Go to Step 13
13
Replace the remote control door lock receiver (RCDLR). Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
Go to Step 14
--
14
Operate the system in order to verify the repair.
Did you correct the condition?

go to the given link and get the solution http://toolsnyou.com/

Testing would need to be done , scan tool hooked up checking DTC'S - diagnostic trouble codes . View data etc...
Keyless Entry System Description and Operation - Active
The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the door locks to unlock the vehicle. Keyless entry will lock/unlock a door or open the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via a serial data message. A low transmitter battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas, such as gas stations that use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following features:
• Door lock/unlock
• Rear compartment lid release
• Illuminated entry lamps
• Panic alarm/Vehicle locator
• Remote vehicle start

Your best bet , take it to a qualified repair shop . Dealer

Pull the Door Handle on the INSIDE of the REAR DOOR, Pull HARD... THEN PUSH IN on the door and then pull back. Mine releases with a Bump of my hip. This is a common issue with these trucks. If you can not get it loose that way, then use a flat screwdriver once you pull the handle to get it to release. You can adjust it to make it work normally,,, I am just too lazy to do mine

1997 Silverado

Is this an issue with all 2008 HHR remotes??? Highly doubtful , probably the vehicles keyless entry system . Taking the vehicle to a qualified repair shop an having the keyless entry system checked for DTC'S - diagnostic trouble code's . Do you know what a DTC is ?
The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the body control module (BCM) to remotely activate certain vehicle features. Keyless entry will lock/unlock the doors, or release the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via a serial data message to the BCM. A low transmitter or vehicle battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following components:
• Door locks
• Liftgate lock
• Remote rear doors (Panel only)
• Vehicle locator/panic alarm
• Illuminated entry lamps
• Remote vehicle start
The keyless entry system has the following components:
• Keyless entry transmitters
• Keyless entry antenna
• 2 Way Advanced Remote Start RCDLR
• BCM

Guessing will not fix this .

Spray a lot of WD-40 or Blaster in the latches on the inside rear of each door. Most likely the drivers door is the issue because it sees the most use. There is a switch on the interior side of the latch that gets stuck. If that does not work, it is possible the GEM module has failed. I believe I have a couple of these if you need one, but usually the switch sticks open (on or depressed and it's normally closed) on the driver door.
Illuminated Entry Illuminated entry is included as a function of the generic electronic module (GEM). The illuminated entry system may be activated in the following three ways:

• Raise the outside door handle (22404).
• Press a code button on the keyless entry keypad (14A626).
• Press the UNLOCK button on the keyless entry remote transmitter (15K601).

Electrical flow through the system is as follows:

• An interior lamp switch (13752) mounted on the front door latch (21812) closes, completing the circuit of the GEM. This switches the system ON.
• This illumination will remain on for approximately 25 seconds and then automatically turn OFF.
• During this 25 second period, the system can be deactivated by turning the ignition switch (11572) to RUN position, locking the doors with the keyless entry remote transmitter or keyless entry keypad or by battery saver time out.
• The system will turn on every time the outside door handles are operated.
• Opening the front doors (20124) or rear doors (24630) from the inside of the vehicle will not turn on the system.
• If the outside door handle is held up so that the interior lamp switch is continuously closed, the system will operate as normal and turn off after 25 seconds.
• If the door handle is still in the raised position, the system will remain off and it will be impossible to activate the system from the other front door handle until the raised door handle is returned to its normal position.
• This is built into the logic circuitry of the system to prevent battery discharge should the outside door handle be propped up or become jammed in any way.

The system consists of:

• generic electronic module (GEM).
• interior lamp switch.
• wiring harness.

The GEM is mounted directly to the fuse junction panel (14A067) The interior lamp switch is retained to the front door latch by a keyed slot and is twisted into position.