One of the most unusual features of the 1967-1972 series of trucks is the unique placement of the 1969-1972 Chevrolet Blazer and GMC Jimmy radio speaker. Unlike the pickup, Suburban, and large trucks; the radio speaker is not under the top of the dash. In fact, the dash does not even have grille slots to allow sound to come from a speaker.
Because of the Blazer and Jimmy’s removable top, GM knew that some would occasionally be caught in the rain. This would quickly ruin a speaker that was in the traditional location. Thus, on the 1969-1972 Blazer and Jimmy only, the factory radio speaker is in the right side interior quarter upholstery panel behind the front seat. If the vehicle did not come with interior rear panels, the speaker was out of sight at the bottom edge of the dash.