In order to mute the City Smart (Autowatch Side Scan) you need to apply voltage to the green mute wire of the Side Scan. This is typically achieved via a rocker switch installed in the cab, but it is also possible to automate this via a Calamp.
As the Calamp voltage output is too low to trigger the mute cable, a relay is required to facilitate this. The below schematic/wiring diagram shows where to connect the relay inline with the Calamp green trigger cable.
It is also possible to add the rocker switch to bypass the relay if an override is required for the driver to use.
AutoWatch Side Scan Left Turn Warning Speaker schematic/wiring diagram:
Calamp 3 Wire Relay schematic: