But for a summary of what has been discussed on the board in the past:
Tom added a switch to send a ground to the trunk release relay.
Information on the WN 14+ trunk release system that has hidden relays.
Here is the diagram for the WM trunk release. The switches send a ground to the BCM. The BCM sends a ground to activate the always on relay. But the BCM only carries this out when the ignition is on.
So as you can see on leg #87 of the relay that goes right to the actuator for the trunk lid. So if we can give that leg 12 volts the trunk will pop. Luckily if you pull the relay you can jump the pins right next to #87 that both have 12 volts in them at all times.
First, the bad news. The relay is basically inaccessible if you just remove the fuse box cover as you can see here.
Once you remove the entire kick panel you can finally see the trunk release relay. But of course to remove the kick panel is a chore. These Items have to be removed: outer seat track cover, threshold, end dash cap, door vent transition cap on the dash, kick panel (2 #15 torx screws - yours ,like mine, might already be broken at the screws so easy off without a tool)
You will pull the relay out and using a wire or paperclip join one of the legs on the left with the one on the upper right of the relay pins. The trunk will pop.
Always On Modification
Now a way to avoid this fate is to convert your trunk release to being active even when the key is off. I took a look at the diagram and came up with the same idea Tom did years ago but I will not have to add a switch anywhere. I figured a way to convert the factory switch to be active all the time. My solution is to bypass the BCM by attaching a wire from the switch to the activation wire. WARNING - disadvantage of this is it will even be able to pop the trunk when you are driving down the highway because this is bypassing the BCM that ordinarily would not allow you to pop trunk while in drive.
Here the red wire indicates how we will bypass.
Since these two wires go to the BCM the best place to join them up is at the BCM. So stretch out and get ready to twist yourself under the dash! Remove the knee panel, 12 and 13's will have the knee airbags as well, remove the foot well HVAC duct and that gives you good access to the BCM plugs.
First took out Plug #4 (Black) from the BCM looking for spot 22. On the bottom row you can see the cavity numbers 19-25 molded on the connector. Count over and you will see the brown wire in spot 22.
I then installed a Posi-tap terminal that pierce the wire insulation a little ways up the wire. These Posi-taps are nice in that you do not have to cut the wire and they are easy to work with in tight spaces.
I then stripped and installed a length of wire (3 inches or so) into the other end of the Posi-tap.
Next was BCM plug #2 (White) and I looked for spot 10. Numbers on the connector were harder to see on this one but you can count over from the top 1-4 then the next row is 5-10 and that blue wire is right on the end in cavity #10.
Put another Posi-tap on the blue wire and joined the two wires together.
And here it is all installed and plugged back in.
Now the trunk release works with my key in or out.
You can get a small variety pack of 6 Posi-taps straight from the manufacturer with free shipping for about $9:
Posi Products - small gauge wire posi-tap pack