False trunk open warning lights
 

I have a 2008 G35x that occasionally lights up the trunk open warning light when the trunk is securely closed. If I open and close the trunk the light goes out. But the three times it has happened, the trunk has been securely closed.

I am guessing the sensor/switch might be loose or need replacement; that would be easier to fix than a wire issue. Has anyone had this issue before? Can anyone tell me how to get access tot he trunk closed sensor?

Hello, and welcome to G35Driver. I have not worked on the trunk circuit so I can't say where things are located, nor have I ever heard of anyone with your symptoms here. I wanted to let you know that while I understand your diagnosis, and I hope it is as simple as you describe, the problem has the potential, at least, to be a bit more involved. Looking in the shop manual, there are some 6 pages or so of description involving the trunk lock functionality :52:
The system is entirely controlled by an intermediary logic module (the BCM) which reads inputs from numerous sources and then determines whether or not to trigger the opening of the latch, or the buzzer or dash light for the trunk open condition. The system involves the door locking system, the keyless entry system, etc. .

Nothing happens directly. Just to give you an idea; if you push the trunk open button, it does not just simply close a switch that provides a circuit path for the latch mechanism to operate. Instead, the pressing of the button is constantly being monitored over a communication bus by the BCM which, upon seeing the button "request", determines whether or not to operate the latch. With this level of logic involvement, when troubleshooting a system, you always need to consider that the indicated symptom could be phantom or actual :dunno:

Back to your question though, I'm not sure if the sensor for the trunk open condition is a discrete component, or if it is integral to the latch actuator mechanism, or light switch, or what, so I really can't say where it is. If you do solve this, please respond back here with the answer in case someone else ever lands here from a search.

This has happened to me twice. Both times were after a heavy rain. I didn't know where to look to see what got wet but it hasn't happened since.

Considering your sig line, it would help the OP if you clarify if this was this on a 1st or 2nd gen model, and was it on a sedan or coupe?

Did you ever figure out what the problem was I am having the same issue?

I haven't had this problem yet, but I have had a few instance where the trunk just didn't want to latch and stay latched. Sometimes all I had to do was pull the inside release handle, other times i had to hit the internal release button/switch. Haven't yet figured out the cause, but next chance I get (after the weather starts warming up) I plan to dig into the latch mechanism and release button and see it something has gotten in there and caused this.

Thread revival, but maybe I can save someone else from feeling stupid like me. "Tore into" the mechanism, cleaned it and greased it. Put it all back together and it still didn't want to stay latched all the time. I then thought, hmm, maybe it thinks that the key is still in the trunk. I pulled the physical key out of the fob (just in case) tossed the fob in the trunk and closed it, it didn't stay latched. Tossed the fob on my workbench, 10 out of 10 times it stayed latched. I felt dumb, but was happy to have figured it out. I couldn't tell if there was a sensor built into the latch or not as I didn't disassemble it completely.

Fob in the trunk lol

Except it was only actually in the trunk for the test, other than that it was always in my pocket

Your car is so smart yet acting so stupid. Lol

I mean, the fob was in the pocket closest to the hatch, basically right above the edge of the bumper, so I get it. It's more annoying when using the door button to lock the car and it thinks it's inside and just beeps.