Back-Up Power Source Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Back-up Power Source Circuit

Back-up Power Source Circuit

DESCRIPTION

This is the back-up power source circuit for the air conditioning amplifier. Power is supplied even when turning the power switch OFF and is used for diagnostic trouble code memory, etc.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (ECU-B)
(a) Remove the ECU-B fuse from the driver side junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.

2. CHECK AIR CONDITIONING AMPLIFIER (+B VOLTAGE)




(a) Remove the air conditioning amplifier with connectors still connected.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:






OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.

3. CHECK WIRE HARNESS (AIR CONDITIONING AMPLIFIER - BATTERY AND BODY GROUND)




(a) Disconnect the A8 amplifier connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:





(c) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER