I don’t believe this topic is covered in the 124 Spider Owner’s Manual, so by being familiar with the two pages copied from the MX-5 manual (shown below) regarding emergency access to the trunk, the knowledge just might come in handy some day when you are unable to access items in your trunk due to a dead battery, or an inoperable electrical trunk release. Apparently the cap, once exposed and unfastened (with a Phillips stubby), is attached to the same cable that actuates the phosphorescent mechanical button located on the rear trunk panel (near the trunk latch – see diagram to the right), and will serve as an alternate pull-handle to the federally mandated manual release for anyone trapped inside the trunk.
The trunk latch cover panel in the 124 Spider is a much better design than the MX-5’s, as contents in the trunk were able to interfere with the release latch action and prevent the trunk from opening (as shown in kentbigdog’s animated gif below). However, be aware that care should be taken to keep oversized luggage from pushing too hard on either panel, as it may cause the release to bind.
The first thought that comes to mind – in vehicles outside of the U.S., I wonder if this emergency release cable is still present, as I doubt that the interior manual release buttton is present. My guess is that it exists globally as a substitute for a key lock cylinder and linkages to unlatch the the trunk lid, because it is lighter and cheaper.
The second thought that comes to mind – can a person even fit in a 124 Spider trunk? Until I saw this picture of a young lady in the Miata trunk (which is even smaller than our trunk), I didn’t think so. 😉
MX-5 Emergency Trunk Access instructions, courtesy of Mazda