PTC Heater Circuit

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): PTC Heater Circuit
- PTC Heater Circuit

DESCRIPTION

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

WIRING DIAGRAM

INSPECTION PROCEDURE

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

PROCEDURE

1. INSPECT PTC HTR NO. 1 RELAY

(a) Remove the PTC HTR NO. 1 relay from the engine room relay block.

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

Standard Resistance:

NG -- REPLACE PTC HTR NO. 1 RELAY
OK -- Continue to next step.

2. INSPECT PTC HTR NO. 2 RELAY AND PTC HTR NO. 3 RELAY

(a) Remove the PTC HTR NO. 2 relay and PTC HTR NO. 3 relay from engine room relay block.

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

Standard Resistance:

NG -- REPLACE PTC HTR NO. 2 RELAY OR PTC HTR NO. 3 RELAY
OK -- Continue to next step.

3. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Remove the air conditioning amplifier assembly with its connectors still connected Removal.

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

Standard Voltage:

Text in Illustration

HINT
*: After the measurement conditions are met, wait 30 seconds before performing measurements.

NG -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (For Automatic Air Conditioning System)
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - AIR CONDITIONING AMPLIFIER)

(a) Remove the PTC HTR NO. 1 relay from the engine room relay block.

(b) Disconnect the air conditioning amplifier 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. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - AIR CONDITIONING AMPLIFIER)

(a) Remove the PTC HTR NO. 2 and PTC HTR NO. 3 relays from the engine room relay block.

(b) Disconnect the air conditioning amplifier 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.

6. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - QUICK HEATER ASSEMBLY (PTC HEATER))

(a) Remove the PTC HTR NO. 1 relay from the engine room relay block.

(b) Disconnect the quick heater assembly (PTC heater) 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.

7. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - QUICK HEATER ASSEMBLY (PTC HEATER))

(a) Remove the PTC HTR NO. 2 and PTC HTR NO. 3 relays from the engine room relay block.

(b) Disconnect the quick heater assembly (PTC heater) 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.

8. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - BATTERY AND BODY GROUND)

(a) Remove the PTC HTR NO. 1 relay from the engine room relay block.

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

Standard Voltage:

Text in Illustration

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

9. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - BATTERY AND BODY GROUND)

(a) Remove the PTC HTR NO. 2 and PTC HTR NO. 3 relays from the engine room relay block.

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

Standard Voltage:

Text in Illustration

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

10. INSPECT QUICK HEATER ASSEMBLY (PTC HEATER)

(a) Remove the quick heater assembly (PTC heater) Removal.

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

Standard Resistance:

Text in Illustration

NG -- REPLACE QUICK HEATER ASSEMBLY (PTC HEATER) Removal
OK -- Continue to next step.

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

(a) Disconnect the quick heater assembly (PTC heater) connector.

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

Standard Resistance:

Text in Illustration

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (For Automatic Air Conditioning System)