Well, just my luck, the AC cycles at 45 seconds. Go figure. So I gave up and took it to an independent mechanic, who spent two hours on it, and also gave up. Or, rather, did not feel that he could solve the problem within the 3hrs allotted, but would have to follow every wire to determine the source of the problem. So I am taking it to another independent and, after that, if the problem is still not diagnosed ... well ... I guess I will just have to roll it off a cliff.
Any other suggestions?