Wh at causes my lift lock not to lock on my srx 2005 cadilac because all my other doors lock using my keyless remote?

Body Control Module (BCM)
Below the left side of the I/P to the left of the steering column.
Has three connectors.connector #1 52-Way F AMP Hybrid (BK) Body Control Module (BCM) C1 Pin
Wire Color
Circuit No.
Function
1
TN
860
Front Windshield Wiper Switch High Signal
2
WH
1459
Security System Sensor Supply Voltage
3
PK
1439
Ignition 1 Voltage
4
TN
28
Horn Relay Control
5
OG
300
Run Relay Control
6
TN
707
RAP Relay Coil Control
7
TN/WH
1969
Headlamp High Beam Relay Control
8
--
--
Not Used
9
PK/WH
1970
Headlamp Low Beam Relay Control
10
WH
1080
Park Lamp Relay Control
11
YE
749
Security Indicator Control
12
GY
91
Windshield Wiper Switch Signal 2
13
YE
196
Windshield Wiper Motor Park Switch Signal
14
TN
1835
Low Reference
15
L-GN/BK
1137
DRL Ambient Light Sensor Signal
16
YE
5066
Brake Pedal Position Sensor Signal
17
BK/WH
1651
Ground
18
--
--
Not Used
19
BK/WH
151
Ground
20
BK/WH
1651
Ground
21
YE
5
Crank Voltage
22
PK
1239
Ignition 1 Voltage
23
BN
1141
Accessory Voltage
24
--
--
Not Used
25
WH/BK
644
12-Volt Reference
26
PK/BK
109
Hood Ajar Switch Signal
27
OG
5688
10-Volt Reference
28
GY/BK
5689
Low Reference
29
BN/WH
230
Low Reference
30
PK
1444
I/P Dimming Control
31
OG/WH
812
I/P Dimming Voltage
32
--
--
Not Used
33
BN
5077
Low Reference
34
BN/WH
1571
Traction Control Switch Signal
35
GY/BK
1598
Courtesy Lamps Switch Off Signal
36
PK/BK
1597
Courtesy Lamps Switch On Signal
37
TN/WH
1455
Keyless Entry Signal
38
L-GN
1037
Class 2 Serial Data
39
L-GN
526
Stop Lamp Supply Voltage
40
L-GN
80
Key In Ignition Switch Signal
41
L-BU/WH
1314
Left Front Turn Signal Lamp Supply Voltage
42
D-BU/WH
1315
Right Front Turn Signal Lamp Supply Voltage
43
GY/BK
690
Courtesy Lamp High Control
44
OG
1732
Inadvertent Power Courtesy Lamp
45
--
--
Not Used
46
RD/WH
340
Battery Positive Voltage
47
OG
228
Windshield Washer Pump Control
48
GY
8
Instrument Panel Lamp Supply Voltage
49
D-GN/WH
1135
A/T Shift Lock Control Solenoid Control (w/o AQW)
GN/WH
1135
A/T Shift Lock Control Solenoid Control (AQW)
50
RD/WH
240
Battery Positive Voltage
51
RD/WH
2440
Battery Positive Voltage
52
RD/WH
1240
Battery Positive Voltage
Connector #2 52-Way F Receptacle 0.64, 2.8 (BK) Release Tool/Test Probe: 12094429/J-35616-4A
Body Control Module (BCM) C2 Pin
Wire Color
Circuit No.
Function
1
--
--
Not Used
2
OG/BK
780
Driver Door Lock Switch Lock Signal
3
D-GN
5512
Liftgate Open Switch Signal
4
D-BU
245
Passenger Door Lock Switch Unlock Signal
5
L-GN/BK
748
Right Rear Door Ajar Switch Signal
6
YE/BK
1181
Right Rear Door Open Switch Signal
7
L-BU/BK
747
Left Rear Door Ajar Switch Signal
8
L-GN
1177
Right Front Door Open Switch Signal
9
L-BU
1134
Park Brake Switch Signal
10
L-BU
2380
Rear Parking Assist Chime Signal (UD7)
11
OG/BK
781
Driver Door Lock Switch Unlock Signal
12-15
--
--
Not Used
16
WH
193
Rear Defog Relay Control
17
TN/WH
746
Right Front Door Ajar Switch Signal
18
D-BU/WH
1179
Left Rear Door Open Switch Signal
19-21
--
--
Not Used
22
L-GN
1123
Door Lock Key Switch Lock Signal
23
WH
5075
Current Sensor Signal
24
PU
1124
Door Lock Key Switch Unlock Signal
25
TN
126
Left Front Door Open Switch Signal
26
GY/BK
745
Left Front Door Ajar Switch Signal
27-29
--
--
Not Used
30
WH
17
Stop Lamp Supply Voltage
31
L-BU
244
Passenger Door Lock Switch Lock Signal
32-33
--
--
Not Used
34
PK/BK
1303
Liftgate Ajar Switch Signal (Early Production)
35
YE
2080
Low Reference
36
PK
2435
Low Reference
37
YE/BK
2079
Driver Heated Seat Cushion Temperature Sensor Signal
38
GY
2434
Passenger Heated Seat Cushion Temperature Sensor Signal
39
TN/WH
2430
Passenger Heated Seat Relay Control
40
PU
2477
Driver Heated Seat Relay Control
41
--
--
Not Used
42
L-GN
24
Backup Lamp Supply Voltage
43
YE
18
Left Rear Stop/Turn Lamp Supply Voltage
YE
18
Left Rear Stop/Turn Lamp Supply Voltage
44
GY
8
Instrument Panel Lamp Supply Voltage
45
L-GN
275
Park/Neutral Position Park Signal (E58 w/o AQW)
L-GN
275
Park/Neutral Position Park Signal (E59 w/o AQW)
L-GN
275
Park/Neutral Position Park Signal (AQW)
46
TN
694
Driver Door Lock Actuator Unlock Control
47
--
--
Not Used
48
D-GN
19
Right Rear Stop/Turn Lamp Supply Voltage
D-GN
19
Right Rear Stop/Turn Lamp Supply Voltage
49
RD/WH
440
Battery Positive Voltage
50
BK
550
Ground
51
TN
294
Door Lock Actuator Unlock Control
52
GY
295
Door Lock Actuator Lock Control

The Lock's lock from the door switches ? If they do it's not a fuse problem . Which of these does your vehicle have ?
Keyless Entry System Description and Operation (with Accessory 2 Way Remote)
Keyless Entry System Description and Operation (without Accessory 2 Way remote)

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/liftgate 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
• 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

Your best bet , take it to a GM dealer .

Remote control door lock receiver (RCDLR)

The remote control door lock receiver (RCDLR) is a multifunction module that operates both the keyless entry system as well as the TPM system. When an RF message is received from a keyless entry transmitter, the RCDLR interprets this signal and will request via serial data that the body control module (BCM) perform the specific function, i.e. door lock, door unlock, or vehicle locate.

Remote Control Door Lock Receiver (RCDLR)
In the right rear quarter panel behind the interior trim panel

If it locks when using the manual switch inside the car, the problem is probably your remote. If not, your lock solenoid in the lift gate may need to be replaced.

You have to take you car to the dealer with proof of ownership.

I tried replacing battery in my remote. Sometimes it work and sometimes it doesn't. I think it could be a wiring problem in the remote. I know it's a major paun having to hurry up and put key in ignition befofr alarm starts going off.

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 .

So this answer is on the same topic of a 2005 Ford Focus keyless entry remote. There is no way to "reset" the code from the vehicle, however you can reprogram an existing or program a new keyless entry remote to your Ford Focus by using these simple instructions:

*** THERE ARE 2 POSSIBLE PROGRAMMING PROCEDURES. ***Procedure #1
Note: Obtain all remote transmitters for this vehicle.
Note: Do not depress the brake pedal during procedure.

1. Turn ignition from OFF to RUN 8 times within 10 seconds, with the 8th time ending in RUN. Door locks will cycle to confirm programming mode. (Off is the position where you can remove your key, RUN is the position just shy of starting your car.)
2. Within 20 seconds press any button on the first keyless remote to be programmed. Door locks will cycle to confirm programming. If you only have one remote then skip to step 4.
3. Within 20 seconds, press any button on the second keyless remote. Door locks will cycle again to confirm programming. Repeat step 3. For all other remotes.
4. Turn ignition to OFF. Locks will again cycle to indicate end of programming mode.
   
   Procedure #2
5. Note: Obtain all remote transmitters for this vehicle.1Fasten seat belts and close all doors.
6. Turn ignition from OFF to RUN 4 times within 6 seconds, with the 4th time ending in RUN. (Off is the position where you can remove your key, RUN is the position just shy of starting your car.)
7. Turn ignition to OFF. Acoustic signal will sound and system warning lamp will illuminate to confirm programming mode.
8. Within 10 seconds, press and hold any button on the first keyless remote. Wait for acoustic sound and warning lamp to flash (confirming programming) then release button on remote. Wait 2 seconds but within 10 seconds repeat step 4. For all other remotes. If you only have one remote then continue to step 5.
9. Turn ignition to Crank or wait 10 seconds to end programming mode.

replace the remote key battery.

Lock all the doors from the inside (with all the doors closed), unlock your driver's door by manually lifting the lock, then press it back down after you are out - this will prevent the alarm from sounding when you use the key to unlock the door.