Kia Sportage: Heater / PTC Heater Description and operation
The PTC (Positive Temperature Coefficient) heater is installed at the exit or
the backside of heater core.
The PTC heater is an electric heater using a PTC element as an auxiliary heating
device that supplements deficiency of interior heat source in highly effective
diesel engine. The electric heater heats up the interior by directly heating
the air that passes through the heater. The name itself implies that the element
has a proportional resistance change sensitive to temperature.

Operation Principle
ECM outputs a PTC ON signal and operates PTC relay 1. Then heater controller
operates PTC relay 2 and PTC relay 3 with an interval of 15 seconds.
However, PTC relay 3 can be operated while battery voltage is above 12.4V.
Operating Condition
PTC heater operates according to the following conditions;
• |
Battery voltage: 12.4V or above
|
• |
Ambient temperature and coolant temperature
|
Ambient
Temperature
|
Coolant
Temperature
|
PTC
Operation
|
Below -20°C
(-4°F)
|
Below 75°C (167°F)
|
ON
|
10°C (504°F)
|
Below 65°C (149°F)
|
ON
|
12°C (53.6°F) or above
|
-
|
OFF
|
-
|
80°C (176°F) or above
|
OFF
|

Replacement
1.
Disconnect the negative (-) battery terminal.
2.
Recover the refrigerant with a recovery/recycling/charging station.
...
Inspection
Operating Logic Test (Manual only)
Inspect the PTC operation by confirmation logic as follows;
1.
Entering
(1)
Se ...
Other information:
Inspection
1.
Turn ignition switch OFF and disconnect the negative (-) battery cable.
2.
Remove the crash pad lower panel.
(Refer to Body - "Crash pad lower panel")
3.
Remove the cras ...
1. Open the tailgate.
2. Remove the service cover.
3. Remove the socket from the assembly by turning the socket counterclockwise
until the tabs on the socket align with the slots on the assembly.
4. Remove the bulb from the socket by pressing it in and rotating it counter-clockwise
until ...