Started planting corn several days ago.  Cannot get #1 row to read on the monitor.  Finally had to turn row 1 off on monitor so it isn't screaming at me.  Row 1 is planting.  I checked sensor, checked out OK.  To be safe, I installed a new seed tube sensor.  Still no dice.  The pins on the cab plug in look OK as well as the harness as far as I can tell.  What to check next?  I'm stumped with this one, first time I've had it do this.  Thanks for your time!!!!