A big thank you to you guys who responded to my issue. As I said, I did check the wiring carefully, but apparently not carefully enough. This kind poster put the idea in my head that I should probably check again, paying particular attention to the dcc/dcs switch wires. Once again, I glanced at them and they seemed fine, but upon close examination, one of the wires had broken off the switch and stiffly stayed in a position where it was difficult to see that it no longer made contact. Bright light and reading glasses allowed me to notice it and once I soldered it back, my ABA came back to life!
I am 53. I wear reading glasses. And need the HUGE magnifying glass with a SUPER BRIGHT Goose neck light on the work bench, AND I STILL have trouble seeing those little wires. LMAO
Glad you found the issue. The aggravation is still better than sending the engine out.