Only if you have the electronic climate controls - set a temperature and the system maintains it automatically.
See "Related Questions" below for much more about Taurus/Sable heating systems. That might help you get a 'handle' on what your system is, or is not, doing.
why is my '99 ford taurus making a knock noise and smoking from under the radator
where is the floor jack located on a 99 ford taurus
The defrost fuse on the 99 Ford Taurus is located in the interior fuse box. It is in the number 26 slot.
how to remove a fender on 99 taurus
No
Yes. They should both have the AX4S transmission.
The pollution sensor is detecting unburned hydrocarbons. That usually means a cylinder is misfiring.
The 1999 Ford Taurus does not have a timing belt. It has a chain that requires no maintenance.
134a refrigerant
3/16"
timing chain
Code 19 for a 99 Ford Taurus means the restraint control module crash data memory is full. If you replace the RCM, the code will reset.