Heater Relay Circuit

DESCRIPTION

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

WIRING DIAGRAM

INSPECTION PROCEDURE

1. CHECK HEATER FUSE

1. Remove the HEATER fuse from the instrument panel J/B.

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

   Resistance:

   Tester item	Condition	Specified condition
   HEATER fuse	Always	Below 1 Ω

NG	REPLACE HEATER FUSE

OK

2. INSPECT HEATER RELAY

1. Remove the HEATER relay from R/B No.3.

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

   Resistance:

   Tester connection	Condition	Specified condition
   3 - 5	Always	10 kΩ or higher
   3 - 5	When battery voltage applied to terminals 1 and 2	Below 1 Ω
   3 - 4	Always	Below 1 Ω
   3 - 4	When battery voltage applied to terminals 1 and 2	10 kΩ or higher

NG	REPLACE HEATER RELAY

OK

3. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER ASSEMBLY - BODY GROUND)

1. Remove the A/C amplifier assembly with the connectors still connected.

2. Disconnect the connector from the A/C amplifier assembly.

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

   Voltage:

   Tester connection (Symbols)	Condition	Specified condition
   A11-18 (HR) - Body ground	Ignition switch position OFF Blower switch position OFF	Below 1 V
   A11-18 (HR) - Body ground	Ignition switch position ON Blower switch position ON	Below 1 V
   A11-18 (HR) - Body ground	Ignition switch position ON Blower switch position OFF	10 to 14 V

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE