Toyota 4Runner: Back-up Power Source Circuit

Toyota 4Runner Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / Back-up Power Source Circuit

DESCRIPTION

The back-up power source circuit for the air conditioning amplifier assembly is shown below. Power is supplied even after the ignition switch is turned off and is used for diagnostic trouble code memory, etc.

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 (AIR CONDITIONING AMPLIFIER - BATTERY)

(a) Disconnect the F42 amplifier connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
F42-21 (B) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to Air Conditioning Amplifier Assembly)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

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 heate ...

IG Power Source Circuit

DESCRIPTION The main power source is supplied to the air conditioning amplifier assembly when the ignition switch is turned to ON. The power source is used for operating the air conditioning ampl ...

Other materials about Toyota 4Runner:

Screen Flicker or Color Distortion
PROCEDURE 1. CHECK DISPLAY SETTING (a) Reset display settings (contrast, brightness) and check that the screen appears normal. OK: The display returns to normal. OK END NG ...

Turbine Speed Sensor Circuit No Signal (P0717)
DESCRIPTION This sensor detects the rotation speed of the turbine which indicates the input speed of the transmission. By comparing the input turbine speed signal NT with the counter gear speed sensor signal SP2, the ECM detects the shift timing of the ge ...