Turn engine sinc on/off at the lower helm works fine. Go to the tower and the switch doesn't work. I changed the tower switch no different. The tower green sinc light is on when lower helm switch is on. Pulling the tower switch out and pushing it in just causes the green light to flicker but doesn't effect the operation of the sinc system at all i.e. If it's on it stays on and can not be shut off. If it's off at the lower helm the green light in the tower is off and will not come on. Any ides on what to try next? Is it possible the lower helm switch is bad? My switch set up is on the left.