Hello Rick & welcome,

So you are saying that even AFTER you replaced all of the parts the power is still applied to the solenoid coil ALL THE TIME?

If that's the case it is possibly time to start taking some measurements with a meter - what voltages are present on the base of the output transistor (TIP36C) and the driver to it when you power up? Thi sshould give a clue as to which direction to look - further back from the transistors or further forward in the wiring harness etc?