PTC Heater Circuit

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

DESCRIPTION

The air conditioning amplifier assembly sends operation signals to the PTC HTR relays when quick heater assembly (PTC heater) operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the PTC HTR relays turn on, and power is supplied to the quick heater assembly (PTC heater) installed in the air conditioning radiator assembly.

Quick Heater Assembly (PTC Heater) Operation Condition





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(e) Check the operation by referring to the table below.

Air Conditioner





OK:

Heater Active Level changes normally.

NG -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures
OK -- Continue to next step.

2. INSPECT PTC HEATER RELAY (PTC HTR NO. 1, PTC HTR NO. 2)

(a) Remove the PTC HTR NO. 1 relay and PTC HTR NO. 2 relay.





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

Standard Resistance:





NG -- REPLACE PTC HEATER RELAY
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (PTC HTR NO. 1 RELAY, PTC HTR NO. 2 RELAY - POWER SOURCE)

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

Standard Voltage:

PTC1





PTC2





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

4. CHECK HARNESS AND CONNECTOR (PTC HTR NO. 1 RELAY, PTC HTR NO. 2 RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I77 air conditioning amplifier assembly connector.

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

Standard Resistance:

PTC1





PTC2





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

5. CHECK HARNESS AND CONNECTOR (PTC HTR NO. 1 RELAY, PTC HTR NO. 2 RELAY - QUICK HEATER ASSEMBLY)

(a) Disconnect the I41 quick heater assembly connector.

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

Standard Resistance:

PTC1





PTC2





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

6. INSPECT QUICK HEATER ASSEMBLY

(a) Remove the quick heater assembly Removal.

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





Standard Resistance:





Text in Illustration





NG -- REPLACE QUICK HEATER ASSEMBLY Removal

OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal