PTC Heater Circuit

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

DESCRIPTION

PTC heater relays are closed in accordance with signals from the air conditioning amplifier and power is supplied to the quick heater assembly installed on the heater radiator heater unit sub-assembly.

WIRING DIAGRAM

INSPECTION PROCEDURE

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

PROCEDURE

1. INSPECT PTC HEATER RELAY (PTC NO. 1, PTC NO. 2, PTC NO. 3)

(a) Inspect the PTC heater relays Testing and Inspection.

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

2. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BATTERY)

(a) Remove the PTC heater relays from the No. 2 engine room relay block.

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

Standard Voltage:

Text in Illustration

(c) Reinstall the PTC heater relays.

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

3. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BODY GROUND)

(a) Remove the PTC heater relays from the No. 2 engine room relay block.

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

Standard Resistance:

Text in Illustration

(c) Reinstall the PTC heater relays.

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

4. PERFORM ACTIVE TEST USING TECHSTREAM (HEATER ACTIVE LEVEL)

(a) Remove the PTC heater relays from the No. 2 engine room relay block.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Air Conditioner / Active Test / Heater Active Level.

(f) Measure the voltage when changing the control range with the Techstream, according to the value(s) in the table below.

Standard Voltage:

Text in Illustration

(g) Reinstall the PTC heater relays.

NG -- CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY)
OK -- Continue to next step.

5. INSPECT QUICK HEATER ASSEMBLY

(a) Inspect the quick heater assembly. Testing and Inspection

NG -- REPLACE QUICK HEATER ASSEMBLY Service and Repair
OK -- Continue to next step.

6. PERFORM ACTIVE TEST USING TECHSTREAM (HEATER ACTIVE LEVEL)

(a) Disconnect the A44 quick heater assembly connector.

Text in Illustration

(g) Reconnect the quick heater assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (PTC HEATER RELAY - QUICK HEATER ASSEMBLY)

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

7. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Remove the PTC heater relays from the No. 2 engine room relay block.

(b) Disconnect the D17 air conditioning amplifier assembly connector.

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

Standard Resistance:

(d) Reconnect the air conditioning amplifier assembly connector.

(e) Reinstall the PTC heater relays.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal