Hilux loud click on full left lock

Do yourself ( s ) a favor, do not turn anything on full hard lock, go there for a split second, then back it off a little...
It may also pay to have your " limit-locks " looked at, or greased..
They just look like bolts
They are located on the inside of your front wheel hubs, on the backing plate, ( my Navara has 2, front and rear, on each ) and their job is to stop you turning the wheeels too far left or right,,
It may be as simple os smearing a dollop of grease on each and also in the slide they rub on..
If you still hear the it then have the power steering looked at

Cheers Mate
Bucky

As Bucky said, My old Rocky started doing this and a dollop of grease on the limiting bolt/pin fixed it. It was worse if on full lock and moving over a bump etc.

Another potential is CV joints. Check the boots to see that they are not damaged and letting grease out / dirt and water in. Clicking on full lock is often an early indicator of CV problems.