For anyone new to this problem it is caused by a bad lead between the pedal and the amp.
Some of the stock leads provided by fender are wired the wrong way round. Tip to sleeve and sleeve to tip. This confuses the diodes in the foot switch, making them think the drive channel is engaged.
A new wire (mono jack to mono jack using speaker cable not guitar cable)will fix the problem
Answers & Comments
If the footswitch is not switching correctly, open it up and check for any shorts or a defective switch. Sounds like it's a problem with the switch.
For anyone new to this problem it is caused by a bad lead between the pedal and the amp.
Some of the stock leads provided by fender are wired the wrong way round. Tip to sleeve and sleeve to tip. This confuses the diodes in the foot switch, making them think the drive channel is engaged.
A new wire (mono jack to mono jack using speaker cable not guitar cable)will fix the problem