Toyota 4Runner: Air Conditioning Control Panel Circuit

Toyota 4Runner Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Automatic Air Conditioning System) / Air Conditioning Control Panel Circuit

DESCRIPTION

This circuit consists of the heater control assembly and air conditioning amplifier assembly. When the heater control assembly is operated, signals are transmitted to the air conditioning amplifier assembly through the LIN communication system.

If the LIN communication system malfunctions, the air conditioning amplifier assembly does not operate when the heater control assembly is operated.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (HEATER CONTROL - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the F42 amplifier connector.

(b) Disconnect the F29 control connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F29-10 (LIN1) - F42-37 (LIN1)	Always	Below 1 Ω
F29-10 (LIN1) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	CHECK HARNESS AND CONNECTOR (HEATER CONTROL - BATTERY AND BODY GROUND)

(a) Disconnect the F29 control connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F29-4 (IG+) - F29-11 (GND)	Ignition switch off	Below 1 V
F29-4 (IG+) - F29-11 (GND)	Ignition switch ON	11 to 14 V

Standard Resistance:

Tester Connection	Condition	Specified Condition
F29-11 (GND) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of wire harness connector (to Heater Control Assembly)

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	REPLACE HEATER CONTROL ASSEMBLY

(a) Replace the heater control assembly with a new or normally functioning one (See page ).

(b) Operate the heater control assembly to check that it functions properly.

OK:

Heater control assembly operates normally.

END (HEATER CONTROL ASSEMBLY IS FAULTY)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

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