No heat The temp. gauge is two points above Cold, Fans runs in all positions except floor position. It shuts off. Changed thermostat, no change. Hoses going to heater core are HOT, but cold air is all that comes intto car. A/C is not working due to leak in system, should this affect the climate control system during winter?

No Blower in Floor Mode
A customer arrives with a 1983 to 1995 Full Size Ford, Lincoln, or Mercury
automobile with automatic temperature control. If the complaint is no blower operation when
the floor mode is selected, the vehicle may have a problem with the thermal blower lockout
switch also referred to as the CELO (cold engine lock out switch).
The thermal blower lock out switch is located in the heater core intake hose. The two
wire switch has a thermal element with a small set of contacts, the contacts are open when the
coolant is below 120°F and closed when the coolant is above 120°F. The thermal blower lock
out switch also contains a vacuum switch, which applies vacuum to the outside/recirculate
valve when the system is in the floor position. When the engine coolant is below 120 degrees
and the selector is set to floor position, the thermal blower lock out prevents blower from
turning on and closes off the outside air during engine warm-up. When the coolant
temperature is above 120 degrees, and the selector is set to the floor position, the thermal
blower lock out switch allows the blower to operate and opens the outside air door.
In order to diagnose this problem, test the thermal blower lockout switch with the
engine at normal operating temperature (above 120°F). Unplug the wire harness connector
from the thermal blower lockout switch. Using a 15-amp fused wire, jumper the harness
terminals to test the switch. If the blower comes on, the thermal blower lock out switch is
faulty. If the blower doesn’t come on, look for an open between the control head selector and
thermal blower lock out switch.
In some cases the blower may continually run even when the engine temperature is
below 120 degrees. Unplug the thermal blower lock out switch and if the blower motor turns
off, the thermal blower lock out switch is faulty. If the motor continues to run, look for a
short to power between the control head selector and thermal blower lock out switch

Try bleeding your cooling system. if there is air in any of your system it will not warm the interior of your car. nothing to do w/ your a/c. check for bleeder valve around thermastat housing. or add antifreeze each mornig until it holds no more. hope this helps