Waiving prelim means that you are essentially saying that the State has probable cause to file charges against you. You should check with a lawyer who practices in your area about whether this means you give up claims of probable cause to arrest, although I don't think it does.
Edward J. Blum
There may be a motion to suppress the evidence here. Based on the recent United States Supreme Court case of Arizona v. Gant, your husband needed to be within reaching distance of the vehicle's interior for the search to be valid, unless (1) the arresting agency has a valid policy regarding vehicle searches that covers this situation; OR (2) the police were legitimately looking for evidence of a crime. I doubt either exception applies here, but I am working with limited facts.
Generally, you do not give up the ability to bring a motion to suppress by waiving a preliminary hearing.
A word of caution regarding preliminary hearings: If your husband could be charged with another crime(s) based on the information that is likely to come to light at a preliminary hearing, it may be better for him to waive the preliminary hearing. If evidence to support charges other than the ones already pending comes to light, the prosecution may elect to add those charges; and your husband could be facing those charges, as well as the ones he currently faces.
In any event, your husband needs to discuss this issue with his lawyer and come to an informed decision.