AIR CONDITIONING SYSTEM (for Manual Air Conditioning System) > Heater Control Switch Circuit

for Preparation Click here


DESCRIPTION

The No. 1 heater control (A/C switch) is powered through the HTR IG fuse. The No. 1 heater control (A/C switch) transmits operational signals of each switch to the air conditioning amplifier.

WIRING DIAGRAM


E177087E01


INSPECTION PROCEDURE

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

1.INSPECT NO. 1 HEATER CONTROL SUB-ASSEMBLY

  1. Remove the No. 1 heater control sub-assembly (A/C switch) (Click here).



    E145243E23

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

Standard Resistance:
Tester Connection
Switch Condition
Specified Condition
2 (L) - 4 (B)
A/C Switch: off
10 kΩ or higher
2 (L) - 4 (B)
A/C Switch: on
Below 1 Ω

  1. Check that the indicator light comes on.

    OK:
    Measurement Condition
    		Switch Condition
    		Specified Condition
    Positive battery - 2 (L)
    Negative battery - 3 (E)
    		A/C Switch: off
    		Indicator light off
    A/C Switch: on
    		Indicator light comes on

  1. Reinstall the No. 1 heater control assembly (A/C switch).

Text in Illustration 
*1
Component without harness connected
(No. 1 Heater Control Sub-Assembly (A/C switch))


NG
REPLACE NO. 1 HEATER CONTROL SUB-ASSEMBLY (Click here)
OK


2.CHECK HARNESS AND CONNECTOR (NO. 1 HEATER CONTROL SUB-ASSEMBLY - BATTERY)


    E130392E30

  1. Disconnect the D7 No. 1 heater control sub-assembly (A/C switch) connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    D7-2 (L) - Body ground
    		Ignition switch off
    		Below 1 V
    D7-2 (L) - Body ground
    		Ignition switch ON
    		11 to 14 V

  1. Reconnect the No. 1 heater control sub-assembly (A/C switch) connector.

Text in Illustration 
*1
Front view of wire harness connector
(to No. 1 Heater Control Sub-Assembly (A/C switch))


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK HARNESS AND CONNECTOR (NO. 1 HEATER CONTROL - AIR CONDITIONING AMPLIFIER)


    E176773E01

  1. Disconnect the D7 No. 1 heater control sub-assembly connector.

  1. Disconnect the D16 air conditioning amplifier connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D7-3 (E) - D16-28 (LED)
    		Always
    		Below 1 Ω
    D7-4 (B) - D16-27 (A/C)
    		Always
    		Below 1 Ω
    D7-3 (E) - Body ground
    		Always
    		10 kΩ or higher
    D7-4 (B) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the No. 1 heater control sub-assembly connector.

  1. Reconnect the air conditioning amplifier connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioning Amplifier)
*2
Front view of wire harness connector
(to No. 1 Heater Control Sub-Assembly (A/C switch))


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)