Is there any heat or is it restricted ? I would flush the heater core with a garden hose. You can do that with a Prestone kit (about $5.00) or take both heater hoses off at the firewall, buy a section of heater hose at the hardware store and get an adaptor to hook one end of the heater hose to a garden hose. Pull the car on the street, hook the garden hose to it and let it rip. That will clean it out and give you heat. As far as the floor heat...The door to the floor is not operated by vacuum, but by electric. You can see that if you open the glove compartment and then push down on the part that lets the glove box swing down beyond the stop. Start the car and change positions on the air control while looking at the doors. The one to the far right is only for full A/C. The one toward the middle, I believe, is the one that opens the door to the floor. If it isn't moving, perhaps a fuse blew, or the switch there needs to be replaced.