You can find this information from John Sherbit-MOTOR MANUAL/MOTORALLDATA Distributor
You can find this at you local public library...........
On a 2000 Mercury Cougar : That's your Anti-theft system status light
When the heater resistor goes, your climate control fans will only work on the fourth setting. You can get a new resistor from any Ford Lincoln Mercury dealer, though they may have to order one.
Your thermostat is stuck open.
location of heater control valve on 2005 mercury marguis ?
where is the heater control valve
http://www.coolcats.net/tech/troubleshooting/heatercore.html
On a 1994 Mercury Cougar, the heater control valve is typically located near the firewall on the passenger side, connected to the heater hoses that run between the engine and the heater core. It may be mounted on the engine compartment side of the firewall or integrated into the heater core assembly. To access it, you may need to remove any covers or components obstructing your view. Always consult a repair manual for specific instructions and diagrams for your vehicle.
To change the heater core on a 1988 Mercury Cougar, first ensure the engine is cool, then disconnect the battery. Remove the dashboard and the center console to access the heater core housing. Disconnect the hoses from the heater core, remove the mounting bolts, and take out the old core. Install the new heater core by reversing the disassembly steps, reattach the hoses, and reassemble the dashboard and console.
The best way to find the location of a part on your car is to go to Autozone.com Once there, create an account, add your car to "my vehicles." In search key in part you are looking for, to the left of the part you should see "View Job Diagram." Click on and a repair guide image showing location of part will come up. The diagram will show the climate control system for heater related parts such as the Blend Door Actuator, Heater Core, Heater Hose Clamps, Heater Motor Resistor, Heater Control Vavle, and Blower Motor.
What you may be experiencing is a blown resistor. If the heater only works when on 4, but not 3, 2, or 1, then it is most definitely the answer. If it is, there is plenty of info on this at newcougar.org.
To replace the heater motor on a 1999 Mercury Cougar, first disconnect the negative battery cable and remove the passenger side lower dash panel for access. Next, locate the heater motor, which is typically found near the firewall. Disconnect the electrical connector and remove the mounting screws to take out the old motor. Install the new heater motor by reversing the process, ensuring all connections are secure before reassembling the dash panel and reconnecting the battery.