The mixing door isn't working. Take it to the garage as it porbably is the controler. First make sure there is vacuum getting inside the cab from the engine.
If the heater has a sweet smell it could be that the heater core is leaking engine coolant. When the leak gets worse you will have a wet floor on the passenger side and the windshield will fog up when you turn on the defroster.
Heater core.
The heater coil and a heater core is the same thing. Hot water circulates from the engine and through the heater core then back to engine generating heat for your heater system.
A water thermostat stuck open. Air in the heater hose lines (caused by low radiator coolant). Air temperature (mechanical) control cable not opening the heater hose water valve (under hood).
To fix a Jaguar S type heater, check the diverter mechanism. It shunts air through the heater core, which may not be operating properly.
Assuming your temperature selector is not on "cold", the heater core is likely bad
you would have to see a mechanic about that problem
If the heater in a 1997 Mercury Mountaineer is not working, it could be due to several issues. Common causes include low coolant levels, a faulty thermostat, or a malfunctioning heater core. Additionally, problems with the heater control valve or a broken blower motor can also prevent warm air from circulating. It's best to check these components to diagnose and resolve the issue.
Behind / below the glove compartment area inside a plastic case . You can see where the heater hoses connect to the heater core at the firewall in the engine compartment
Behind the glove compartment area inside a plastic case . From the engine compartment you can see where the two heater hoses connect to the heater core at the firewall
Mercury Mountaineers have a "blend" door in the heater box. It is probably malfunctioning. You can find more info by searching for Ford + "blend door" or "no Heat"
Your heater core is leaking in it's housing box and blowing moist air through the heater/defroster. Try bardall radiator stop leak. If no help, install new heater core. Chuck.
no
Jump start car and do not run heater with engine not running.
Probably because coolant level is low
The heater in a 2000 Mercury Mountaineer may turn off due to several reasons, such as a malfunctioning thermostat, a faulty heater control valve, or issues with the climate control system. It could also be caused by low coolant levels, which can affect heating performance. Additionally, electrical issues or a blown fuse could interrupt the heater's operation. Diagnosing the specific cause typically requires a thorough inspection of the heating system.
left side of the engine after the cat