I have eliminated the battery (it is new/fully charged as was the battery from sons car I tried w same results) I took the starter off and had it tested at auto parts store.Test light shows voltage at starter. Illiminated security (had a 99 with that problem know what it looks like)
Have since found the the relay in and out repeated latching sound when key is in on position : it is coming from the Idle Air Control Valve on the throttle body. Am thinking this is a sympton rather than a cause since it should not keep motor from cranking.
When the key is turned to start there is the click from the relay in fuse box (have exchanged a known good relay) Nothing from the starter. Assume ignition switch is doing its part since relay gets start signal.
Have not considered locked motor : 45,000 miles & running fine when parked in garage ( and the starter would still kick in even if it could not turn motor) Because of the position of the starter, with the car on jack stands, and my favorite person under the car, I don't want to try shorting solenoid, in case it might jump off (or weld a scew driver to my hand)
I was not aware of a main ground stud. That might be a good lead. I will check it out. If that doesn't pan out I guess I'll have to buy a code scanner and see if that will direct me. Thanks for reply.
