I have an aqua source shower faucet and when it is turned all the way on the water only gets warm it will not go to full hot water how can I fix this

Read this,

How To Adjust a Single Lever Shower Faucet - Self Help and More,

AND

How to Adjust an Aquasource Shower Faucet | eHow

And view these videos and see if they solve your problem.

https://www.bing.com/videos/search?q...ment&FORM=VDRE

https://www.bing.com/videos/search?q...er&FORM=RESTAB

As you see from the videos most shower faucet have a way to adjust the temperature, be it single or double handles.

As indicated above, there is more-likely anti-scald ring installed. Remove handle and readjust the ring to give you more hot water

Milo