You do not indicate whether or not the blower is running. Can you hear it? If not then follow the previous suggestions and check the bar fuse near the master cylinder and the controller.

If you CAN hear it blowing, then remove the glove box and use a vacuum source on each of the lines from the switchover manifold. If you have any leaking other than the defrost pod, then replace them all. If the defrost pod is the only one leaking you can replace it without removing the dash.

Good luck,