This might help. Best thing (if you get into trouble), see a lawyer.
Words in quotes (" ") needs to be followed up with the definition pertaining to.
I'm talking about the 4th Amendment.
Automobile Exception.
If the police have "probable cause" to believe that a vehicle such as an automobile contains, "contraband", "instrumentalities", or "evidence" of a crime, they may "search" the vehicle without a warrant.
Rationale.....Automobiles are mobile and so will not likely be available for search by the time an officer returns with a warrant.
Moreover, the Supreme Court has declared that people have a lesser expectation of "privacy" in their vehicles than their homes.
Note: If the police have "probable cause" to believe that the car itself is "contraband", it may be seized from a public place without a warrant.
1) Scope of Search
If the police have full "probable cause" to "search" a vehicle, they can “search” the entire vehicle (including the trunk) and all containers within the vehicle that might contain the object(s) for which they are searching. Thus, if the police have "probable cause" to believe that drugs are within the vehicle, they can search almost any container, but if they have "probable cause" to believe that an illegal alien is hiding inside the vehicle, they must limit their search to areas where a person could hide.
a) Passenger's Belongings
The "search" is not limited to the driver's belongings and may extend to packages belonging to a passenger. Like a driver, a passenger has a reduced expectation of privacy in a car.
b) Limited Probable Cause
If the police only have "probable cause" to "search" a container (recently) placed in a vehicle, they may "search" that container, but the "search" may not extend to other parts of the car.
2) Contemporaneousness Not Required
If the police are "justified" in making a warrant less "search" of a vehicle under the exception at the time of stopping, they may tow the vehicle to the station and "search" it later.