Audio Control Switch Inspection

Disconnect the negative battery cable.
Remove the driver-side air bag module. (See DUAL-STAGE DRIVER-SIDE AIR BAG MODULE .)
Disconnect the audio control switch connector.
Measure the resistance and inspect for continuity between the cruise control switch terminals using an ohmmeter.

If not as specified, replace the cruise control switch.

Fig 1: Measuring Resistance And Continuity Between Cruise Control Switch Terminals
Courtesy of MAZDA MOTORS CORP.