Heating / Air Conditioning

IG Power Source Circuit

~2min read
DESCRIPTION

The main power source is supplied to the A/C amplifier when the ignition switch is ON.

The power source is used for operating the A/C amplifier and servo motor, etc.

WIRING DIAGRAM
CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

Start the engine before inspection. Check the IG1 relay or battery if the engine does not start.

PROCEDURE
  1. INSPECT A/C AMPLIFIER

(a) Remove the A/C amplifier with its connectors still connected.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

D47-1 (IG+) - D47-14 (GND)

Ignition switch off

Below 1 V

D47-1 (IG+) - D47-14 (GND)

Ignition switch ON

11 to 14 V

Text in Illustration

*1

Component with harness connected

(A/C Amplifier)


OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG
  1. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)

(a) Disconnect the A/C amplifier connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

D47-1 (IG+) - Body ground

Ignition switch off

Below 1 V

D47-1 (IG+) - Body ground

Ignition switch ON

11 to 14 V

Text in Illustration

*1

Front view of wire harness connector

(to A/C Amplifier)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
  1. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D47-14 (GND) - Body ground

Always

Below 1 Ω

Text in Illustration

*1

Front view of wire harness connector

(to A/C Amplifier)


OK

REPLACE A/C AMPLIFIER


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

Test yourself

A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.