without going into all the details that it could be or what it takes, an easy way to check the solenoid is to hook a testlight or voltmeter on the small post that has the yellow/red tracer wire on the starter solenoid. Ground the other lead of light or voltmeter to good ground. Have someone turn key switch to engage starter and see if you have voltage here. this will tell you if your getting the power from the key switch to engage the solenoid. You can also ck the ground this way by grounding your testing device to the small post with the black wire on it at the solenoid and repeating this ck. If vvoltage is good here the solenoid needs replacing. (sometimes you will even here a solenoid click or engage but no starter movement because the contact between the two big post is not making the connection from the red positive wire to the yellow starter wire ) I say this because sometimes even if you hear a solenoid click its no good.
