Trunk will not open with the door OR remote buttons. I can it hear it "clicking" but it is not releasing the trunk lid. I do not have a key for the trunk. What could the problem be?

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 .

Do you know anything about automotive electronic's ? The trunk release is controlled by electronic control modules . Having the vehicle check for DTC'S - diagnostic trouble code's should be the first step in the diagnostic procedure . Then reading how it work's !
Factory service repair info.
Rear Compartment Lid Release System Components
• Body control module (BCM)
• Remote control door lock receiver
• Interior rear compartment lid release switch
• Exterior rear compartment lid release switch
• Rear compartment lid release actuator
• Trunk release relay

Rear Compartment Lid Release Operation
The interior rear compartment lid release switch receives a signal from the driver door switch assembly (DDSA). When the interior rear compartment lid release switch is activated, the signal circuit is pulled to ground. The DDSA interprets this and sends a GMLAN serial data message to the body control module (BCM) requesting the rear compartment lid be released. The BCM responds by applying battery voltage to the trunk release relay control circuit which energizes the TRUNK RELES relay. The trunk release relay is supplied with battery voltage at all times. With the relay coil energized, the relay switch contacts close allowing battery voltage to flow to the rear compartment lid release actuator causing the rear compartment lid to release. The rear compartment lid release actuator is permanently grounded at G402.

The trunk release relay is located in the rear fuse box located under the back seat.

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

Hi Jeff,
I was going to say, check fuse/ jump the load side of relay Good post.

How about a key ?

Luggage Compartment Description and Operation (Sedan)
Rear Compartment Lid Release
The rear compartment lid can be released in one of three ways:
• Inserting the key into the key lock cylinder, if equipped
• Operating the rear compartment lid release switch
• Using the keyless entry fob
To operate rear compartment lid with the rear compartment lid release switch or with the rear compartment release button on the key fob, the gear selector may be in any position, but vehicle speed must equal 0 for the rear compartment lid to release.
When the rear compartment lid release switch is pushed, the rear compartment lid release signal circuit to the body control module (BCM) is grounded. BCM then grounds the coil side of the trunk release relay through the trunk release relay control circuit. With this voltage is applied to the rear compartment lid release actuator, opening the rear compartment.

do you know how to do electrical testing ?

Circuit/System Verification
Ignition ON, observe the scan tool Trunk Release Switch parameter while pressing and releasing the rear compartment lid release switch. The parameter should change between Active and Inactive.
? If the parameter does not change, refer to Trunk Release Switch Malfunction.
Command the trunk release with a scan tool, the rear compartment lid latch should release the trunk lid.
? If the rear compartment lid latch does not release, refer to Rear Compartment Lid Latch Malfunction

You may want to take it to a repair shop .

I would check the owners manual or with Cadillac - its possible the remotes lost part of the signal and need to be reset. It sounds like the receiver is not getting a signal from them by using that button.
Could be the receiver too.

Lower the back seat and crawl into the trunk and see what the latch is doing when you activate the key fob. the trunk lid will have to be open to enable any repairs. Also an emergency release cable is probably visible (yellow handle) inside the trunk and will Open the trunk lid.

If the actuator mechanism is functioning (you hear the click) the next step is to see if the cable is connected to the latch. Open your trunk and press the button - watch what happens. You may have to manually 'lock' the trunk with the trunk lid open to observe the action. You can always unlock this latch with your key if necessary.

Let me know what happens ... good luck

Thanks for using FixYa.cop

You can try this I think the latch is just slightly missaligned.Did you put something in the trunk and push down on the trunk?Try to push down hard on the trunk where the latch is a few times while pressing the remote.If this works and it opens look for marks on the latch indicating rubing,file down,spray with WD 40.Good Luck.

If you will turn the ignition on, press & hold the door lock release button to the left . . . . viola!