Here is a video showing you how to make the trunk open on Ertl diecast, it is just two plastic pins that they wedge between the unshaped hinge and the body, this keeps the trunk from opening, Just remove the chassis, and push out the two push pins and the trunk is now operational.
Note, if you lose audio while the video plays just move the play bar back a little bit and the audio will come back, you might have to do this a couple of times but that will get the auto working again.
Very neat but it's hard to understand why would the manufacture do that?
Joshua J. Shy
Very informative vid. I've performed this "operation" several times myself. Many Ertl's (mostly the non-hobby editions) have a "closed" but not sealed trunk. One can easily fix that. I've also cut open (and added hinges) many "molded shut" trunks. I love a good trunk!