Different manufacturers put them in different places but they re usually at the headstock under a cap just behind the nut or where the neck joins the body just under.
Guitar truss rod direction.
Loosening a truss rod turning counter clockwise adds relief to decreases tension on the neck which results in increased higher string action height.
Adjusting guitar truss rods.
A little truss rod adjustment goes a long way as you can see by measuring your string height before and after with a string action gauge.
Adjusting the truss rod of your guitar alters your guitar s neck relief the amount of bow in the neck measured by the distance between the strings and the frets.
Some bow is necessary for a guitar to play well but you don t want it to be bowed too much.
When adjusting a truss rod in either direction you are changing the force applied to the rod.
While the amount of relief is a matter.
If your guitar truss rod is fully turned to either direction but yet still your guitar neck doesn t move or it is turning but does nothing to your guitar neck here is what you can try.
The neck of most guitars has what s known as a truss rod which is a one or two piece adjustable metal rod that goes down the inside of the center of the neck.
Truss rod adjustments are made to alter the straightness flatness of the neck truss rods often require adjusting after changing string gauges or when temperature and humidity change the amount of bow in the neck.
Whichever setup you prefer a straight neck is a good starting point.
With a properly functioning truss rod you probably won t need more than 1 8 turn in either direction to get what you re after.