Tims, I dont have a 455, but I think the switch is the same as a 425. On the Switch circuit board, there is a small green led light, which indicates you have power. With the Switch on, that should be lit, If not you have no power at the switch. I'm not sure about terminal B, but are you positive you has voltage going into the switch??
You can run a lead from the solenoid to the lead wire coming from the switch just to make sure.
You can run a lead from the solenoid to the lead wire coming from the switch just to make sure.