Heating Problems

[jrbud08]

I have an '02 Kia Optima and my heater went out. It blows cool air and the windows fog up a little bit, but not enough to distract my driving. My check engine light has been on since the heater went out. My temperature gauge stays at halfway as it always has. My water and antifreeze levels are full. I have been told it could be my heater core or maybe my thermostat. Can anybody help me please?

[swiftknight23]

it one of a couple of possible problems. 1. your heater core is faulty or 2. heater control valve isnt opening.

Take this vehicle to a shop specializing in heater repair and
have the mechanic inspect both the heater control valve and
the device that activates the valve. Upon his diagnosis, have
the necessary repairs done. In this particular situation, some
mechanics may suggest replacing the heater core in addition
to fixing the heater control valve problem. They'll claim the
heater core is clogged and therefore is contributing to a low
air temperature heater output. Although there may be some
truth to this, nine times out of ten, fixing whatever is wrong
with the heater control valve will dramatically improve heater
performance. In other words, in most cases, replacing the
heater core won't add that much to the heater's performance

We can understand this diagnosis by understanding how a
standard automotive heater works.
First off, there is the "heater core". It is located behind the
dashboard vents and looks like a mini-radiator. Essentially,
the sole purpose of the heater core is to emit heat. Where
does this heat come from? Well, hot coolant from the
engine is circulated through it. The fan (a.k.a. blower) blows
air through the heater core, out the vents, and thus into the
passenger compartment.
So then, how does the heater control valve fit into all of this?
It controls the flow of coolant to the heater core. If the valve
is open, coolant will flow to the heater core and thus the fan
will blow warm air out the vents. If closed, coolant won't flow.
Hence, the air isn't warm.
It should now be clear that since this vehicle's heater blows
air that isn't warm, the heater control valve must not be
opening. This is either because the valve itself is faulty or
the device activating it is.

hope this helps

Terrell