Donald George`

Thanks Eugene.  That makes good sense, I should have thought of that.  Actually, now that you mention it, I did connect my multimeter to the two blade terminals (with both wires plugged into them) and when I turned the key to start, there was no voltage, indicating to me a broken circuit, like you said, probably on the ground side.  It was only when I connected the positive lead of the multimeter to the yellow wire (while unplugged from the solenoid) and the negative lead to a direct ground that I got the 12.5 volts.  So it makes sense that the black wire on the other blade connector, which should be the ground to complete the circuit is not grounded. 

As soon as I get the chance, I'll try your suggestion.  If it works, then the black wire is likely not grounded.  Then the question becomes: is the black wire  "ungrounded" because of  a damaged or broken wire somewhere causing a break in the circuit,  or is one of the safety switches not made, purposely causing the break in the circuit?  I guess I'll cross that bridge when I come to it!   Thanks again!  Stay tuned.