Heater Relay Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Heater Relay Circuit

Heater Relay Circuit

DESCRIPTION

The heater relay is switched on by signals from the A/C amplifier. It supplies power to the blower motor.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK FUSE (HTR)





(a) Remove the HTR fuse from the engine room R/B.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FUSE (HTR)
OK -- Continue to next step.
2. INSPECT HEATER BLOWER MOTOR RELAY





(a) Remove the heater blower motor relay from the engine room R/B.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE HEATER BLOWER MOTOR RELAY
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (HEATER BLOWER MOTOR RELAY - BATTERY)





(a) Remove the heater blower motor relay assembly from the engine room R/B.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (HEATER BLOWER MOTOR RELAY - 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.
5. CHECK HARNESS AND CONNECTOR (HEATER BLOWER MOTOR RELAY - AIR CONDITIONING AMPLIFIER)
(a) Check for open and short circuit in the harness and the connector between the heater blower motor relay and the A/C amplifier.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE