Steering Pad Switch Circuit

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: Steering Pad Switch Circuit
- Steering Pad Switch Circuit

DESCRIPTION

The R/F, TEMP UP (+), and TEMP DOWN (-) switches are located on the steering pad switch assembly. The resistance of the steering pad switch assembly changes in accordance with switch operation. The A/C control assembly outputs voltage to the steering pad switch assembly and reads voltage changes due to the resistance changes that result from switch operation.

HINT
If there is an open in the circuit, the A/C system cannot be operated by the steering pad switch assembly.

If there is a short in the circuit, the resulting condition is the same as if the switch were continuously depressed. Therefore, the A/C control assembly cannot be operated by the steering pad switch assembly, and the A/C control assembly will not be able to function correctly.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
The vehicle is equipped with a SRS (Supplemental Restraint System). Before servicing (including removal or installation of parts), be sure to read the precaution for Supplemental Restraint System Service Precautions.

PROCEDURE

1. INSPECT A/C CONTROL ASSEMBLY

(a) Disconnect the connector from the spiral with sensor cable sub-assembly.





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

Standard Voltage:





Text in Illustration





NG -- CHECK HARNESS AND CONNECTOR (A/C CONTROL ASSEMBLY - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR

(a) Disconnect the connector from the navigation receiver assembly*1 or radio and display receiver assembly*2.

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

Standard Resistance:





*1: w/ Navigation System (for Navigation Receiver Type) or w/ Audio and Visual System (w/o Daytime Running Light)

*2: w/ Navigation System (for Radio and Display Type) or w/ Audio and Visual System (w/ Daytime Running Light)

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. INSPECT STEERING PAD SWITCH ASSEMBLY

(a) Disconnect the connector from the steering pad switch assembly.





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

Standard Resistance:





Text in Illustration





NG -- REPLACE STEERING PAD SWITCH ASSEMBLY Removal
OK -- Continue to next step.

4. INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY

(a) Disconnect the connector from the spiral with sensor cable sub-assembly.





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

Standard Resistance:





NOTICE:
The spiral with sensor cable sub-assembly is an important part of the SRS airbag system. Incorrect removal or installation of the spiral with sensor cable sub-assembly may prevent the airbag from deploying. Refer to the pages shown in the brackets.

HINT
* Removal Removal
* Installation Installation
* The spiral cable makes a maximum of approximately 5 rotations.

Text in Illustration





NG -- REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Removal
OK -- Continue to next step.

5. CONFIRM MODEL

Result:





B -- REPLACE NAVIGATION ECU SUB-ASSEMBLY

C -- REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY
A -- Continue to next step.

6. REPLACE NAVIGATION ECU SUB-ASSEMBLY

(a) Replace the navigation ECU sub-assembly with a known good one and check if the same problem occurs again Removal.

OK:

Same problem does not occur.

NG -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System

OK -- END (NAVIGATION RECEIVER ASSEMBLY WAS DEFECTIVE)

7. REPLACE NAVIGATION ECU SUB-ASSEMBLY

(a) Replace the navigation ECU sub-assembly with a known good one and check if the same problem occurs again Removal.

OK:

Same problem does not occur.

NG -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System

OK -- END (NAVIGATION RECEIVER ASSEMBLY WAS DEFECTIVE)

8. REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

(a) Replace the radio and display receiver assembly with a known good one and check if the same problem occurs again Removal.

OK:

Same problem does not occur.

NG -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System

OK -- END (RADIO AND DISPLAY RECEIVER ASSEMBLY WAS DEFECTIVE)

9. CHECK HARNESS AND CONNECTOR (A/C CONTROL ASSEMBLY - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)

(a) Disconnect the connector from the A/C control assembly.





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





Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE A/C CONTROL ASSEMBLY Removal