So I am a new 2000 discovery 2 owner recently and it of course has all the common problems but I am stuck in trying to get it into low gear. the cable moves freely when I disconnect it from the cable at the bottom end. Is it most likely the lever it’s attached to seized up or the solenoid that is the problem​​​​​​​

 

Search for transfer case solenoid and you'll find the cause of the issue. In your photo, it's located in the bottom right part of the photo, sort of under where the two wire bundles cross, under a metal housing with four bolts that sort of looks like a top hat.

 

That was it I had started yesterday thinking it was just going to be the lever or cable cause I didn’t see a whole lot about the solenoid. Anyways when I tried taking it off yesterday I was trying to get to it without taking the hi low cable mount(bracket with 4 bolts) witch made it impossible mostly because of a electrical bracket mount that was being held in place by that. Now to deal with the three amigos and upgrading to locking diff upgrade

 

99% of time it's your solenoid. It's designed to fail in the locked position. I replaced it with a blanking plate after removing it; you'll find it's significantly easier to put back without the giant cylinder getting in the way of your ratchet.

You're finding out now that the "simple" way has a tendency to be both longer and more difficult than doing it right. Take the cable and electrical connectors off; you'll thank yourself later when you can actually get a socket on the bolts without being a contortionist.

Generally speaking, your Three Amigos are going to be either the shuttle valve switch or one of your wheel speed sensors. Get a OBD2 reader than can scan Wabco codes.

I put a post on here on how to install an electrically actuated CDL if you want to try that. It'll be significantly cheaper than an Ashcroft CDL kit, and you're already halfway done just having the tunnel open.