Thanks. All began working properly when I figured it out earlier. Since when I adopted my car it was essentially a barn find, almost nothing had been rewired since it left the factory. The wires to and from the switch were as they were back in 1966, complete with their unreliable Lucas connectors. I just did not know which wires from the motor went to which wires from the switch because, while they were similar, there were no complete matches. In other words, the solid green from the motor did not go to a solid green wire from the switch, but a green an red.
One other thing I learned and should mention is that after about a week, my motor stopped working again while driving over a rough road. Disheartened, I went and bought a remanufactured motor from XKs Unlimited (they ended up with a motor in their stock in the mid 90s and had no use for it. (I used to have an XKE, so I am a previous customer of theirs). Then, before I could do any new work to the car, I inadvertently touched my knee near the steering column and the original motor started working again. I moved my knee and it stopped working again. After a little fiddling, I understood that there is a common ground wire that connects to a bracket under the dash in that area that was loose. I tightened it and all is wonderful again with the original motor.
Lesson learned: Before going out and spending money on electrical parts, do yourself a favor and check all the ground connections you can find, even if seemingly unrelated to an electrical part that seems to be having problems. As for me, I now have yet another spare Tiger part in my collection, which has grown to absurd proportions over the last years. Ugh.