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G35 Coupe: The trunk release wiring is broken after 5 years.

After repeatedly opening and closing the trunk four times a day for the past five years, the trunk release module has officially stopped working for my G35 coupe. Pressing the trunk release button from under the dashboard and remote fob can no longer open the trunk. There is no key hole to open it either. When the buttons stop working, it is impossible to open the trunk from the outside of the G35. How inconvenient. What happened was that the wire was completely cut into two pieces. Fortunately, the problem can be fixed for under $30 and takes about an hour.

Where the Wires Are

I spent a good chunk of the time trying to figure out which wire was cut, and where to place the new wire. It’s hard because I didn’t want to cut open the plastic tubing. (FYI: Do NOT cut open the tube. Water can leak into the wires and cause more damage). The fix is straight forward after finding the root cause. You just need some tools and patience.

Tools Needed

• A soldering pen ($20)
• No more than two feet of speaker wire ($3)
• A flat head screw driver

The regular speaker wire (those ones with red and black wires attached together) worked well because the wire comes in pairs. In case other wires break, I can just use the extra wire. You can use other type of wires too, as long as the are thick enough to allow enough current to pass through. But be careful not to choose wires that are too thick, as it will not fit well with the black plastic tubing.

Workaround

As a temporary solution, the trunk latch can be released from the inside (thank god). In the middle of the back seat, reach your fingers into the gap between the back portion and bottom portion of the seat, you will find a red nylon tab. Pull on the tab to release the trunk latch.

Disclaimer: This article is for your reference only. I am trying my best to describe how I fixed the problem and not responsible for any damages.

Steps to Fix the Trunk Wiring

1. Open the trunk from inside the car.

2. On the right hand side of the trunk, you will see a black plastic tubing. The wires are located inside the tubing. Again, do not cut the tubing.

3. The two ends of the tubing are fitted into the metal parts. It’s difficult to descibe, but the tube just slides into the opening of the metal. Use your fingers and nails to slide the tube out from both ends.

The broken wire can be located once you slide the tube out.

4. Next a cover needs to be partially removed. If you stand behind the opened trunk, locate the big piece of plastic (carpet like) cover under the speakers. The cover can be removed by taking out the round clips using a flat head screw driver. There are quite a number of clips. Just remove the ones on the right so that you can access the wires.

5. After removing the cover, you will see the bunch of wires from underneath. Try to locate the broken wire. In my case, the broken wire is in green.

Under the carpet-like cover, you will see the wires bundled together by a wrap. The wrap can be opened without breaking it.

6. Because there is no way for me to reconnect the green wire from inside the tube (without breaking the tube of course), the reconnected wire will need to be placed outside (unfortunatelly). Be super careful when doing this: From underneath the trunk, slowly pull the green wire out from the tube. Use extreme caution and do not pull out other wires.

The broken green wire under the carpet-like cover and plastic tube slid out.

7. By now, you should be able to locate the two ends of the broken wire. The wire cannot be soldered back together since it is not long enough to run from the outside of the tube. Even if it can, there is too much stress on the wire and it can break easily. This is where I use the speaker wire. Carefully crimp the two ends of the green wire (there is very little room for error here. Make sure you only crimp the amount you need. In my case, I crimped about 1cm on each end.)

8. Solder the speaker wire to the green wire. Make sure the wire is long enough to stretch as the trunk closes, and there should be no stress on the wire. You only need to use one of the two wires (red or black). The extra one is for spare in case other one break in the future. Cover the soldered points with wiring tape.

Soldered wire and taped up.

9. Test the fix with the remote key fob before putting everything back together.

10. Put the covers back on, and carefully slide the plastic tube back into the metal holes. Because the new wire is outside of tube, it needs to be tucked between metal hole and the exterior of the tube. The gap is very tight, but it should be fine if the wire is not too thick.

I placed some plastic tape around the edge of the tube for cushioning.

11. Lastly, strap the new wire onto the plastic tubing so there is no loose wire.

The fix is done!

The fix works very well for me on my G35 coupe. Hope it will work for you too.