Problem solved! Bit the bullet and resigned myself to the fact that I may have received a new defective cable. Found pinout diagrams for eTrex and DB9 connectors and wiring. Found no continuity between them for the Output. The cable I purchased also has car power adapter built in. Where the 2 wires come together, inside the cig lighter plug, they were sealed with heat shrink but not connected inside the heat shrink! Soldered, reinsulated, reassembled, hooked up to PC and voila, instant response. Downloaded 10 cache waypoints for tomorrows attempt at my first "find".
As noted, cable has external power adapter built in. Have read warnings of overvoltage output with some of these. While the meter was handy I checked it in the car and I am getting 3.3V, thankfully.
Thanks for all of the suggestions.
Happy navigating, Jim