1999 Ford Windstar ABS, Engine and Trac Lights stay on

I took my Van to the Used car dealership that I bought it from because it wouldn't pass e-check because the engine light was on solid. The other two mentioned above are all on. When you disconnect the battery and reconnect it, the engine light is off, but the other two remain on. Of course, when the engine resets as it does after you drive it for a while, the check engine light comes back on. They claimed that they fixed it, but I think that they just disconnected the battery, because the engine light came back on after driving a few miles. They also did something to the circuit that controls the ratio and electronic locks because they worked before I left it with them. The key is fine, because I took it to Auto Zone and tested it. I checked fuse #6, and it was fine. It is not getting power to the circuit. The main problem is the three warning lights (all solid). I was and electronic tech when I was working, but not for cars. I worked on my own cars when I was younger, that is before cars had electronic systems. I have the schematics and the factory owner's manual. Can you give me an Idea as to where to go from here? I am on my THIRD temporary tag, and I cannot get another one to buy more time (expires May 9th, 2009). I am on SSDI and cannot afford not to do this myself. I am very poor right now. I don't have much to give; I am a recent widow. Please help me!
Thanks, chris1999FordWindstarSE

I do have a repair manual that has schematics. So far I haven't found a circuit that is related to this issue. I continue to look. Thank you for the feedback.
Chris