my heater works, but not through the vents just the floor and defroster...
Any suggestions?

do you mean no air comes out the vents, or just not hot air? If no hot air comes out, but air does come out then that seems normal. My LeSabre, and both of my family'* Bonnville'* are like that too.

one of your vacuum tips is unplugged, check under the dash by the drivers side, your going to find a circle with 8 nipples and pipes, the main one to switc (actuator) is probably unplugged, reconnect and bam , your functions for floor / def/ and vent should work again :o