I own a 2005 Ford Freestar (3 button) and the key fob broke at the key ring area. I didn't have much luck with the snap together models already available here so, I made my own screw together design. I did find a similar design from 2012 but this one was made mostly from scratch/sketch. I can verify the guts from both the 3 and 4 button key fobs fit ok.
You'll need two m2 x 8mm screws to assemble.
Printed at .3mm layer height in PETG @240c / 100c bed. Printed with one outer shell (since 100% infill anyway). I suppose you could use supports for the recessed holes in the top half of the case but I didn't need to.
Designed in Fusion 360, sliced in S3D.