If you have a Miata with a factory console trunk release, you already have a good security feature that you don't know about. And thanks to Mazda, you can't even use it! Now you can.
Problem: The only problem with the console trunk release is that it simply isn't secure. It only takes a hard pull to break open the console cover when it is locked, exposing the remote release. This makes it VERY easy to get into the trunk of the Miata. If you need truly secure storage in your Miata you were out of luck. Some people simply disconnected the cable for the remote release. While this solution did secure the trunk, it also removed the convenience of having the remote release. There is a better way if you are willing to do a little work.
Solution: If you have the console release, you have the ability to temporarily disable it. The factory trunk latch has a function built in that disconnects the remote release when activated. To activate this function all you need to do is put the key in the outer trunk lock and turn it backwards (counter-clockwise). That's the catch! For some reason Mazda installs a lock cylinder that only allows rotation in one direction, which prevents this feature from being used. I have discovered how to modify the lock cylinder to allow backwards rotation.
This modification has been successfully performed on both M1 (1997 and earlier) and M2 (1999) Miatas with factory console releases. However, the two types have different lock cylinders which makes the method of modification slightly different for the two types. The details vary depending on which model you have. Use the links below for detailed instructions for your model.
(2000 already includes this feature.)
Just completed the mod to the trunk lockset which enables you to disengage the console release with the key. In addition to previous posts concerning cautions, I add the following:
Once you have the lockset loose and the tag light assembly removed for access to the lock, removal and replacement of the lockset out of its hole is the hardest step. For me it required pressure through the key opening along with manipulation with my hand inside the compartment. The only way I could apply enough pressure was to push on the housing of the lockset with a screwdriver pushed through the key opening of the body panel while I pulled from the inside.
I suggest that you put masking tape around the openingss that you have to access to prevent accidental damage to the paint.
The cap which is removed from the lockset is very flimsy aluminum. If it is not securely tightened when replaced over the keyway door, it will not keep the keyway door in place. I experienced this twice. To increase the friction and pressure of the cap against the lockset, I wrapped the edge of the lockset with electrical tape. This way when I replaced the cap on the lockset body, I could get a tighter fit against the lockset. All of the rest is as described in the mod instructions. BTW, I did install the lockset upside down the first time. Note which way is up before you take the control arm off of the lockset assembly.
Took about 1 hour and 30 minutes for the first time. It's a great mod. I wondered about doing it at first but I had several times thought that storing things in the trunk would be less anxious if the console lock was disengaged. Now I can leave the console unlocked all of the time.
Removing and reinstalling the lock mechanism is described as the hardest step. This can be made easier by adding an additional step: Before you remove the lock, remove the rear license plate and holder. Behind the plate are two bolts with recessed Torx-style heads. Remove the right bolt with a #30 star driver and the plastic above the rear bumper will move further away from the trunk. This will make it easier to remove or install the trunk lock mechanism.
Last weekend I was doing the mod to the trunk lock. I had just the lock out and the trunk was closed accidentally. Unfortunately, the console release mechanism doesn't work with the lock removed. So... I had to fish for the arm that goes from the lock to the latch mechanism. I tried for a couple of hours Saturday then again for a bit on Sunday. Then Monday morning I went to a dealers lot and looked again and measured the distance from the lock hole to the hanging arm and went fishing again. The main problem seemed to be the console release cable gets in the way a bit so you need to bend the fishing bar slightly back so it will arch around the cable. After about a half hour I got it and grabbed it with some hemostats (long skinny needle nose type device) and pulled and voila the trunk opened and I was quickly able to re-install the lock mechanism. A warning/advisory should be added to the instructions that closing the trunk with the lock out is a VERY bad thing. The safe thing to do is to trip the latch mechanism with the trunck open (using a screw driver or such) and the trunk cannot then be closed.
I did this modification to my '93,and the final result is welcome. I would suggest to anyone that tries it to spend the extra 15 minutes it requires to remove the entire rear fascia and tail light assemblies. It will make the removal of the lock assembly easy. I tried working out the lock, by removing only the one tag light on the lock side, and after having wasted 10 minutes, I wished I had gone with my original instinct to remove the fascia. On my lock the flapper door spring broke due to corrosion, and I wasted another hour first trying to bend some wire into that shape, and then to solder the two broken pieces together. Neither worked and It turns out that the flapper door and its spring are not absolutely needed. Also, after I installed the cylindar, it worked, but sometimes it caught a bit when turning counter clockwise. I simply filed down the outside of the tumblers a bit and the whole thing is seamless now. Make sure you wash the assembly with some WD-40 sprayed into all recesses to get any metal particles out of the tumblers, and finish with some powdered graphite lube or a pulverized pencil lead into the keyway. Total time with all my errors was three hours.
My elapsed time -- not working time -- was about 2-1/2 hours. First I had to repair the grinding tool (a brush holder had fallen out . . .) and then, even though following my own taping advice below, allowed the tumbler keeper to fall out. Some of the time was spent driving to my local lock shop for a replacement spring.
On my '97 it would have been virtually impossible to remove the lock mechanism without loosening the rear fascia. It need not be removed completely; just remove the right taillight lens and undo the fascia fasteners from the right corner (below the taillight) through the two screws behind the license plate. The fascia will then easily flex enough to give room for lock removal. I found a "fingers-on-a-stick" ideal for handling the lock.
Then when you remove the tumbler, wrap a piece of masking tape around it to prevent parts loss and also to keep metal chips out of the mechanism. Unwrap only when you are ready to reassemble the lock, but be sure to watch out for the keeper and its spring (see above).
The modification was well worth the effort, and I sincerely thank whoever discovered that this mechanism was already built into the lock mechanism. I castigate Mazda for not activating the feature right from the start.
I own a 1997 Mazda Miata, and have successfully carried out the mod. as instructed by Miata Net members. Upon assembly, however, I realised that when the key was inserted and turned anticlockwise (as prescribed by other Miata.net members) the trunk release disable feature could not be activated (i.e.no popping sound) as there was too much slack on the aluminium rod that connects the lock cylinder to the lock mechanism. (i.e the rod would move backwards but not enough to activate the trunk release disable feature ) To correct this, I removed the rod from both the cylinder and the lock mechanism, and bent both rod ends slightly inwards (towards each other) thus shortening the rod length by approx. 5mm. I replaced the rod and tried again, and although it would still not work, the slack had become considerably less. I thus removed the rod for a second time, and bent it slightly at the point where it forms a "Z", thus shortening the length of the rod by another 5 mm. After replacing the rod, the modification worked perfectly. Although the shortening of the rod required in my case was only about 1 cm, this value is only approximate, as other users may need to shorten it further. It is a process of trial and error I guess. One thing I can advise people who attempt shortening the rod, is to bend the rod only a little each time and try whether it works before bending it more; if the rod is over bent, the mod will not work as there will be no clearance between the vertical metal beam situated in the center of the rear panel and the rod.