No, being pulled over for a broken taillight would not, without more, give the authorities the right to search your vehicle or you. However, there are many circumstances under which they could search you:1) There was a search warrant for you--as may have been, if the DEA (who don't normally get involved in traffic stops) was keeping an eye on you;2) There was an arrest warrant (including a bench warrant, such as for non-appearance in court) for you;3) You consented to the search--for example, they said, "we'd like to search your car" or something similar, and you either explicitly agreed, or acted in a way (nodding you head; getting out of the way so they could search; gesturing at them to continue; etc.) consistent with consent; or4) you acted in some way suspicious (evasive, trying to hide something or moving it out of sight, etc.) which did provide probable cause.