PTC Heater Circuit

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: PTC Heater Circuit
- PTC Heater Circuit

DESCRIPTION

The PTC heater assembly is installed in the heater radiator unit and operates when engine coolant temperature is low and normal heater effectiveness is insufficient.

The A/C control assembly switches the circuit in the PTC relay and operates the PTC heater assembly when the operating conditions (cooling water temperature is below 65°C (149°F), setting temperature is MAX. HOT, ambient temperature is below 10°C (50°F) and blower switch is not OFF) are met.

The number of circuits operated in the PTC heater is controlled according to the overall electric load of the vehicle and charging system output (DC-DC converter built into inverter with converter assembly). therefore, troubleshooting should be performed with other electrical components turned off.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT PTC HEATER ASSEMBLY

(a) Remove the PTC heater assembly.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- REPLACE PTC HEATER ASSEMBLY Disassembly
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - BODY GROUND)

(a) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - NO. 1 INTEGRATION RELAY)

(a) Disconnect the PTC heater assembly connector.

(b) Disconnect the engine room relay block and junction block (No. 1 integration relay) connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - NO. 1 INTEGRATION RELAY)

(a) Disconnect the air conditioning amplifier assembly connector.

(b) Disconnect the engine room relay block and junction block (No. 1 integration relay) connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. REPLACE NO. 1 INTEGRATION RELAY

(a) Replace the No. 1 integration relay Removal.

HINT
Since the No. 1 integration relay cannot be inspected while it is removed from the vehicle, replace the No. 1 integration relay with a new or a known good one and check that the condition returns to normal.

(b) Check if the same problem occurs again.

OK:

Same problem does not occur.

NG -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

OK -- END (NO. 1 INTEGRATION RELAY WAS DEFECTIVE)