[Imrac]

Not sure why it would be so hard to diagnose the solenoid.

Steps: Press the brake while in park. You should hear the click of the Solenoid. If you do, then there is something wrong with the linkage that moves the lockout.

If no click, then go to the solenoid and disconnect the wire and put a voltage meter and press the brake, you should get voltage if the wiring is intact. If you get voltage, the solenoid is damaged.

You can test solenoid by applying the appropriate voltage (probably 12v)

If no voltage, you have a wiring problem.

Shouldn't be that complicated...