I plan on testing with test light and multi meter with the wires on and off. The negative battery is on the alternator bracket and inner fender and are in good shape. Heading to work and will have to get to it this afternoon I hope.
testing WITH the wire on the solenoid will put the "load" on the circuit and cause the intermittent current drop which your bypass circuit is going around. A ground issue is also a possibility especially if it is able to supply just enough current to compensate for the bad ground. But I'm thinking more on the + side
Do keep us posted
