The Dirty Mind of Young Sally (1973)

Sally runs a mobile "pirate" radio station--which she operates from her van--where, in her sexy and sultry voice, she encourages her listeners (mostly teenagers) to use the music she plays "to ball by". She also takes calls from her listeners and even offers herself as a prize in a contest. Her show is so popular it winds up "turning on" large numbers of the local population. The authorities, of course, can't allow that to happen, so they send out the cops to find her and shut her down.