There can be nothing more frustrating that sitting in your vehicle, turning the ignition key and hearing a clicking sound or nothing at all. There can be a number of reasons for a no-start condition, and some of them can be quite easy to remedy. Among other candidates, the starter solenoid will need investigation. Since the starter solenoid uses a high-voltage magnetic relay to transfer electricity from the ignition key to the starter, it can be the likely cause of a starting problem.
Place the vehicle in park or neutral with the emergency brake set. Leave the battery connected for now. Use a floor jack to lift vehicle high enough to place two jack stands under the front part of the frame near each wheel. Lift the rear of the vehicle and place two jack stands under the rear part of the frame near each wheel.
Test the battery voltage with a voltmeter by placing the red positive voltmeter lead on the positive battery terminal. Place the black negative probe on the negative battery terminal. You should read at least 12.5 volts on the meter. The key does not have to be on or in the start position for this check. Charge the battery to full capacity if it reads low.
Slide into the driver's seat and turn the key to the "on" position. Notice the brightness of the dash indicator lights. Turn the ignition key to the "start" position and notice if the indicator lights dim while you do so. If they dim, it means your ignition switch has made correct contact.
Slide under the vehicle with the voltmeter. Remove any splash guard if it impedes access to the starter solenoid. You will see a very thick wire and one small spade push-on wire. Choose the small wire. In the case of a fuel-injected engine, there will be three wires--one thick, one medium (spade) and one smaller spade wire. Choose the medium-size wire.
Remove the medium-size (or small-size) wire and place the voltmeter positive probe inside the wire jack. Place the negative probe of the voltmeter on a good ground source like the frame. Have your assistant turn the ignition key to the "start" position. You should read 12 volts at the wire. If not, the wire needs to be looked at from the solenoid location up to the ignition key source for any breaks or disconnects. Check the main fuse block for a defective relay or starter fuse, and replace if necessary.
Look at the two largest posts on the back of the solenoid. The largest one comes from the battery and will be red. Pick the second-largest post. Take a jumper wire and connect the two posts momentarily. You will see a spark arc, but that will be normal. If the starter motor spins, it means the starter motor has engaged and works properly.
Look at the same two large posts you just jumped. One of them has a thick braided wire running from it to the starter. Stick the positive lead of the voltmeter into the braided wire and ground the negative voltmeter lead against the frame or starter motor housing.
Have your assistant turn the key to the start position. You should hear a heavy clunk, then hear the starter motor engage and crank the engine, while you read 12 volts from the braided wire. If the starter does not activate to crank the engine and you do not read 12 volts at the positive lead, the solenoid has shorted and needs to be replaced.