IG Power Source Circuit
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.
PROCEDUREINSPECT A/C AMPLIFIER
(a) Remove the A/C amplifier with its connectors still connected. |
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(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 |
*1 |
Component with harness connected (A/C Amplifier) |
| OK | ![]() | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)
(a) Disconnect the A/C amplifier connector. |
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(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 |
*1 |
Front view of wire harness connector (to A/C Amplifier) |
| NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)
(a) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
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| 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.

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