Locked box in car...?

[Corksil]

SWIM sometimes carries a bit of his personal stash of chemicals with him when he drives from place to place. Some of his chemicals are sched I, and some are II. He is wondering what the best way is to protect his assets could be. Could anyone clarify the laws in the USA on how they pertain to searching a vehicle? If SWIM were to lock his illegal and suspicious items in a safebox under his seat, and SWIM's car were searched, would enforcement be able to force him to open the box and display the contents?

If SWIM is correct, law enforcement WOULD NOT be able to search the box - assuming it was locked. Because it is a locked box and is not part of the vehicle, a warrant would be needed from a judge granting permission to force entry or order the owner to surrender the contents. How about if there was a suspicious smell coming out? Contents would be some chemicals, a pipe, lighter, eyedrops, and a few other incriminating items.

Can any swimmers validate the aforementioned?