Starter not working

Hi and welcome.

I would start with testing/cleaning up your battery cables. The clicking is the solenoid trying to fire but it doesn't have enough voltage to do so. If you have a multi-meter test the connections from the cable to the battery on + and -. And do the same at the other end of the cables. Positive at the starter and negative to the motor. Make sure you have 000 ohms in all 4 places and the cables are clean. Here is a guide to help with the testing:

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked
https://www.2carpros.com/articles/how-to-use-a-voltmeter

Let me know what you find.

Rich

The clicking is caused by low voltage. When the solenoid fires it pulls an internal contact that is spring loaded. If the voltage is low it fires and the spring pushes it back and it fires and on and on it goes. That is the clicking.

I would recommend ohms testing every connection on both cables and from the cables to where they attach. You should have 000 ohms on all connections. Don't just test the positive cable, a bad ground will do the same thing so test all connections on both cables and test the starter to the block and the block to the body and frame to make sure you have a good ground. The starter grounds to the block and the block to the frame and or body. So if the block isn't grounded the starter won't work.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Let me know what you find out.
Rich