sometimes things in electrical land get goofy. lets see if the solenoid relay is really working. try this, we're going to measure the resistance of the 12v+ cables between battery + to the starter. the starter solenoid creates this connection when you press the start button and 12v is passed thru the harness to the green/yellow connection on the solenoid.
pull the red/12v+ lead off batt
leave your ground jumper on the solenoid in place
hook a multimeter setup to read ohms (200 ohm scale maybe, not too important) between the 12v+ batt cable that you just took off, and the lug on the starter that has the cable that runs between the starter and the solenoid - we're trying to read resistance from the batt all the way to the starter via the fat cables that run through the solenoid. hope that makes sense.
the meter should show that there is no continuity, that the circuit is open.
when the green/yellow on the solenoid gets 12v on it the internal relay should close and allow a connection within the fat cables between the input from the battery and the output to the starter.
ok, here we go:
using a jumper of the same size/diameter/gauge as the wires in the wiring harness, hold the jumper on the solenoid green/yellow connection. then take the other end of the jumper and touch it to batt + (we're doing it this way so as not to have an unfused 12v hot wire hanging off your battery that could short the battery out somewhere on the frame)
if the solenoid relay is working then when you touch the jumper to the battery + terminal the multimeter should change and show continuity/0 ohms/no resistance between the fat cables from the battery + to the starter input.
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