When you buy a new trunk lock for your 2005 Chevrolet Cavalier sedan, it comes with a new key. If carrying a separate key for the trunk is a bother, have the dealer or a locksmith re-key the cylinder to your existing key before you install it.
Inside the trunk lid, turn the back-up light sockets counterclockwise and pull them out of the trunk lid. Remove three nuts -- one on each end of the applique panel and one in the center -- then remove the applique panel from the trunk lid.
Squeeze the tabs on the black plastic housing for the latch cable assembly, then spread the housing open. Pull down, then remove the latch cable assembly.
Remove the lock cylinder retainer -- the big horse-shoe clip holding the lock cylinder to the trunk lid. Remove the lock cylinder, taking care not to lose the spacer behind the cylinder.
To install the new cylinder, fit the spacer over the end of the cylinder and slip the cylinder through the hole in the trunk lid. Install the lock cylinder retainer. Install the latch cable assembly.
Position the applique on the trunk lid and install the nuts. Tighten the nuts to 44 inch-pounds. Insert the back-up light sockets into the trunk lid and turn them clockwise to lock them in place.
