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 assembly and power is supplied to the quick heater assembly installed on the radiator heater unit.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT PTC HEATER RELAY (PTC HTR1)





(a) Remove the PTC HTR1 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 HEATER RELAY
OK -- Continue to next step.

2. INSPECT PTC HEATER RELAY (PTC HTR2)





(a) Remove the PTC HTR2 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 HEATER RELAY
OK -- Continue to next step.

3. INSPECT PTC HEATER RELAY (PTC HTR3)





(a) Remove the PTC HTR3 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 HEATER RELAY
OK -- Continue to next step.

4. 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:





NG -- CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BODY GROUND)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER)





(a) Remove the PTC heater relays from the engine room relay block.

(b) Disconnect the E33 quick heater assembly 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. INSPECT QUICK HEATER ASSEMBLY





(a) Disconnect the E33 and E34 quick heater assembly connectors.

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

Standard Resistance:





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

7. CHECK HARNESS AND CONNECTOR (QUICK HEATER - BODY GROUND)

(a) Disconnect the E34 quick heater assembly connector.





(b) 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 (AIR CONDITIONING AMPLIFIER - BODY GROUND)





(a) Disconnect the E36 amplifier connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal