A/C Signal: Testing and Inspection

A/C Switch

The A/C request signal does not set a trouble code. It may be tested with a voltmeter as follows:

1. With the ignition switch "ON".
At ECU connector B56 terminal 9
A/C switch "ON" 10 - 13 volts
A/C switch "OFF" 0 volts

2. With the engine "ON".
At ECU connector B56 terminal 9
A/C switch "ON" 13 - 14 volts
A/C switch "OFF" 0 volts

Check wiring harness between ECU and A/C switch. Also check A/C switch if above results are not achieved.