Back-Up Power Source Circuit

AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): Back-up Power Source Circuit

Back-up Power Source Circuit

DESCRIPTION

This is the back-up power source circuit for the A/C amplifier. Power is supplied even when turning the ignition switch off and is used for diagnostic trouble code memory, etc.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT CLOCK ASSEMBLY
(a) Turn the ignition switch to the ON position.





(b) Set the time displayed on the clock assembly to any time but 0:00.
(c) Turn the ignition switch to the OFF position.
(d) Turn the ignition switch to the ON position.
(e) Confirm that the time displayed on the clock assembly shows any time but 0:00.
OK:
Time displayed on the clock assembly is any time but 0:00.

HINT: The A/C amplifier and clock assembly use the D.C.C fuse for backup power source. If the D.C.C fuse fails, clock assembly backup power source also fails.

NG -- REPLACE FUSE (D.C.C FUSE)
OK -- Continue to next step.
2. INSPECT FUSE (ECU-B)
(a) Remove the ECU-B fuse from the driver side J/B.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPLACE FUSE
OK -- Continue to next step.
3. INSPECT AIR CONDITIONING AMPLIFIER (B - GND)





(a) Remove the A/C amplifier assembly.
(b) Disconnect the connector from the A/C amplifier.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





NG -- CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)





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





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (D.C.C FUSE - A/C AMPLIFIER)