Lexus NX: Back-up Power Source Circuit

Lexus NX Service Manual / Vehicle Interior / Heating / Air Conditioning / 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 when the power switch is off. The power 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 procedure.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - BATTERY AND BODY GROUND)

(a) Disconnect the air conditioning amplifier assembly connectors.

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

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
I50-21 (B) - Body ground	Power switch off	11 to 14 V

Standard Resistance:

Tester Connection	Condition	Specified Condition
I50-14 (GND) - Body ground	Always	Below 1 Ω

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

SEE MORE:

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE NOTICE: If the auxiliary battery voltage becomes low, windshield deicer operation is canceled to prioritize supplying power to the power steering system. for Power Tilt and Power Telescopic Steering Column: Click here for Manual Tilt and Manual Telescopic Steering Column: Cl

Parts Location

PARTS LOCATION ILLUSTRATION *1 NO. 2 ENGINE ROOM RELAY BLOCK - DCM FUSE *2 TELEPHONE AND GPS ANTENNA (ROOF ANTENNA ASSEMBLY) ILLUSTRATION *1 TELEPHONE ANTENNA (NAVIGATION ANTENNA ASSEMBLY) *2 COMBINATION METER ASSEMBLY *3 MULTI-DISPLAY ASSEMBLY *4 DCM (TELEMATICS TRA

Lexus NX: Back-up Power Source Circuit

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Air Conditioning Unit

Removal

Disassembly

SEE MORE:

Problem Symptoms Table

Parts Location