Why would the heater and AC stop working in a 99 Ford Contour?

If both arnt working it is just the internal fan blower take it to the dealer or mech and have them check the switches first then the blower! good luck

Also, check the fuse in the main fuse box. It will be fuse 37 (light green with a 30 rating listed on it).

Check the main fuse box wiring harness (it's located on the interior drives side, just under the dash if it's an automatic transmission) Look at the main wiring harness coming into the box. It's on the underside of the fuse box and towards the back when it is closed. There is a green wire and fat red wire coming in. The red wire is known to burn out. If the wire look brown theres your problem. Disconnect the battery,pull out the connector and see if the connection is salvagable. Are the pins secure ect. If they are replace the connector to the fuse box. May have to go to a salvage yard to get it or the whole fuse box cause ford wants to sell the whole wiring harness.

Also you could check the relay 14 and the switches.