Solenoid off means the line pressure from the 1/2 shift valve vents and will not move the lock-up valve so the converter will not lock-up. When the solenoid is turned on by the PCM then the vent is blocked so pressure builds to move the lock-up valve over and gives you locked up converter. Ron
This probably answers my question - I had already studied the hydraulic charts and knew the fluid side of it. Your training books must be for the later 2 wire solenoids, since you mention the PCM switches the ground to the solenoid. Both the V/B's we picked up yesterday have 1 wire solenoids that ground through it's mount, and would need 12V+ power applied to function. We will probably just wire a toggle switch supplying power and see what happens once it's in direct.
Thanks for the replies
