700R4 wiring diagramThanks to Lone on the, group for this image.
The lockup can be manually wired by using a normally open, single throw toggle switch wired to connectors A and D. Doing so allows lockup at any speed, just remember to unlock it at a stop, as it apparently will take off, but shudder and shake and not give you the torque multiplication like you need to get rolling. The advantage of using it (lockup converter), is it almost could be considered another gear as the small amount of slipperage is eliminated. It essentially gives you a total locked up 1:1 ratio with the engine just like a manual trans. Here is a picture of the stocking wiring of the tranny: