I've found that my trunk opens randomly at times, don't know why. I've seen this when I start the car up mostly (its also happened whenever I leave the keys in the car but turn it off, and turn it back on) I know the trunk is open because the car tells me whenever I put the car into gear. Anybody have any idea why this might be happening?

 

stop putting people in the trunk

 

haha, very funny....

 

Mine was doing the same thing. Check the trunk button at bottom B pillar, it may get stuck in the in position and can pop open at any time. pull the switch out and clean around the sides. May have some cleaning fluid or debris inside.

 

I have a 1998 C5 and it has been doing the same thing for a long time. It will randomly open. For a while the alarm would go off at night.
Ok, so in looking into this I have multiple problems.
1. Based on doing more home projects and a part time job I started wearing the standard cargo pants with pockets on the side. I would put my wallet in the left side pocket as opposed to the back pocket or taking it out of the back pocket when on longer drive. The wallet on the middle and side of my left thigh was hitting the open button on the door pillar. Ok that was easy to solve.
2. Trunk latch was loose, this caused the trunk to partially open at night and set off the alarm, or while driving. Solution was to remove the trunk liner, it uses clips and I think slides sideways and out (pulled it out a while back) and there are two screws (I think only two) near the tail lights when the deck is closed. I could not figure out why it would not come loose as those screws are hiding under the flock material, and are black as to blend in. I tightened up latch and that solve the partial open issue.
3. I took out the switch on the door pillar. I think it just comes out with small screwdriver or better to use a pry tool. Just avoids scratching paint, and denting plastic part. If you don't have a set, get them. I disconnected the switch. Do not let wires fall into cavity. Tie a string around the wire and tape that to the pillar. I tested switch with a multimeter. Use ohms and continuity settings. Basically no continuity until pushed. I left it of for a few weeks and trunk issue persisted, so I emanated the switch as the problem.
4. It could be a wiring problem. And I might see if there is a way to test that. But not sure exactly how to do that. I am leaning towards replacing the electrical latch unit with a used one. Basically throwing a part at it and see if that works. It does seem to happen more on bumpy roads.
I will update with any new info.

 

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