Land Rover Repair: Range Rover 98 AC, aluminum tube, pressure tube

Question
The AC does not work.. the book icon is on and the ! is there.. under the hood the right side aluminum tube gets HOT and the left side does not change temp.. I just purchased the vehicle so I dont have a history.. Will go bang on the compressor a couple times as recommended and I have read that the compressors can have various issues,.. I believe that I am looking at a compressor issue. Correct? Also changing this out with another used compressor what would the procedure be to DIY it? Do have have to clear all the lines with air and then close it up and then just ad freon? thx!

Answer
On a hot day the high pressure tube should be too hot to touch and the low tube should be cold.  Since that's not happening your first step should be to see whether the compressor is running, and what the system pressures are.  A working system is going to have high side pressure in the 250PSI range and a low side of about 25psi.  

If the system does not have any pressure, it's empty from a leak, and will not run or start at all.

That's where you begin.

Next, you need to find a scan tool to read the climate control faults.  See what is going on there but that is almost certainly a separate issue from the lack of cooling.