Cadillac: fan vents, vacuum leak, caddillac

Question
i have a 1988 caddillac sedan deville, and when i use my fan ( heater or air ) the vents only shoot air fro my dfroster vents. how can i clean my vent to feel the fan in all my vents or what should i do?

Answer
Most cars that old ran on vacuum.  The baffles in the A/C system were controlled when you moved the levers and it would route vacuum to certain vacuum servos that moved the doors... you probably have a vacuum leak on one of the many hoses under the day.  Your best bet is to move the lever to different positions and listen for hissing noises and locate and fix them.  I had the same problem and I did the same thing.