What does the Fender Mustang I & II footswitch do?
You can utilize the Fender one button on/off footswitch (part # 0994049000) with the Fender Mustang I & II and the Fender Bronco 40 amps to switch between two of your favorite Presets.
To use the footswitch with the amp, plug it into the FTSW jack on the top panel of the amp. Then, select the Preset that you want to assign to the footswitch and press the Save button. The Save and Exit buttons will start to flash rapidly. (You can press the Exit button to cancel the operation at this point.) Press the footswitch button again, and select either the Red or Green LED next to the FTSW jack to assign it to the selected Preset. Finally, press the Save button to confirm the footswitch assignment.