I had to reset my ERR 4.1 command diesel board on my Weaver U25B. The directional light's stopped working and the engine would run wild suddenly I had to cut power to the track to stop it. It did this three or four times. Since I reset it everything works properly. I still have to wait to see if it runs wild again. It doesn't do it all the time. When I run the Weaver I stand near the transformer just in case.
I also reset the ERR board on my Williams U33C because the directional lights quit working. Unfortunately, it didn't fix the problem so I connected them straight to the roller contacts. It's not a issue for me. I don't care if they are directional or not. It was something to do and I like to tinker from time to time.