Steering Pad Switch Circuit

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

DESCRIPTION

AUTO, OFF, TEMP UP (+), and TEMP DOWN (-) switches are located on the steering pad switch. The resistance of the steering pad switch changes in accordance with switch operation. The A/C control assembly (heater control base sub-assembly) outputs voltage to the steering pad switch 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 (heater control base sub-assembly) cannot be operated by the steering pad switch assembly, and the A/C control assembly (heater control base sub-assembly) will not be able to function correctly.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT A/C CONTROL ASSEMBLY

(a) Remove the A/C control assembly (heater control base sub-assembly) with the connectors still connected.





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

Standard resistance:





NG -- INSPECT STEERING PAD SWITCH ASSEMBLY

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

2. INSPECT STEERING PAD SWITCH ASSEMBLY

(a) Remove the steering pad switch assembly.

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





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

Standard resistance:





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

3. INSPECT SPIRAL CABLE SUB-ASSEMBLY

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





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

Standard resistance:





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

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

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

(a) Disconnect the connector from the A/C control assembly (heater control base sub-assembly).





(b) Disconnect the connector from the spiral cable sub-assembly.





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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE HEATER CONTROL BASE SUB-ASSEMBLY