My trunk began to self-open about nine months ago. The typical scenario was that after the car was parked in the sun for a couple of hours, the trunk would unlatch and I would hear three soft beeps. This was quickly followed by the alarm going off and the doors unlocking. I performed many checks and inspections over the ensuing months as the problem grew worse. After reading many posts on trunk-latch issues, I decided the problem was related to a defective trunk-latch mechanism. I installed a new one ($200), but, unfortunately, this had no effect. There were no DTCs being thrown, but I was recently beginning to suspect the rear electronics module was the issue.

While replacing the struts on the car, my independent had to remove the trunk liners to gain access. While doing so, he noted that the tape wrapping the large wiring loom exiting the cabin to the trunk had been unwound and the wiring splayed. Since I had alerted him to the trunk problem, he took a close look at the wires and found that the insulation on the white/green lead to the trunk-latch “Ajar Switch” switch had a slight scar/opening in a position where the loom passed over a body seam. He reinsulated the wire, rewrapped the tape, and repositioned the loom to its correct location. Problem solved. The wire had likely expanded ever so slightly in the heat, touched the body seam, and completed an unwanted short to ground.

I hadn’t done any work in this area and didn’t think to look at the wiring entering the trunk. However, in checking my records, I noted the previous owner had the trunk latch replaced under warranty shortly before I purchased the car in 2010. Perhaps this was the cause, or later warranty work done to address an alarm issue after I purchased the car. I suspect one of the dealer techs was researching a problem and neglected to restore the wiring to its as-built condition. It is some comfort to know that the problem was not a Jaguar design issue, but the tech should have done a better job of completing the task. Aside from finally solving a very nagging problem, I’ll gain some satisfaction from selling the slightly-used trunk latch.