I have a 2003 mercury sable fan blows low setting high setting just fine no heat what could cause this?

Marvin

• 85242 Answers
• Posted on Nov 28, 2008

SOURCE: 2002 saturn heater

The problem is the blower motor speed control resistor, it is located near the blower motor in the housing.

SOURCE: 1999 Mercury Sable cooling system

does it blow out white smoke?  If so it might be a head gasket issue.  I know mercury sables were infamous for head gaskets.

Mike Butler

• 6674 Answers
• Posted on Jun 01, 2009

SOURCE: FAN DOES NOT BLOW AIR OUT ON LOWER SETTINGS ONLY ON HIGH

Need a new blower motor resistor. Check under hood on firewall, on passenger side under cowl, behind strut tower area is usual spot. If not may be on housing/ducting under dash on passenger side near blower motor.

SOURCE: Why does my 2001 Mercury Sable climate control only blow heat?

It could be the door that should be shuting off the heater core area is not shuting.The door works with engine vaccuum.The vac. comes from the intake manifold. With your car being a few years old, the heat from the engine may have caused the vac. hose to dry out and crack or become disconnected. With the engine cold and off, look under the hood. A small size vaccuum hose should be connected to the intake manifold and run inside the cabin area. This is one thing you can check. I hope this helps you.

SOURCE: Heater doesn't put out heat.

could be your temp control actuator which is under the dash