Brake controller

[hayfarmer]

Hi all, new member here, and new (PROUD) owner of a 04 -D.S. c/w spartan chassis i have been reading the forum with great interest and find a lot of very useful info. but still have not got the answer to my question, here goes.
I will be towing an 18' flat deck trailer and need to install brake control, i have found the wireing harness for trailer brake and and have proven all lights work and the BLUE wire for brake is installed at the plug, but where is the POWER wire for brake control and how do i find brake switch wire?
Do i have to install a new hot wire from 12 volt source ? Part of my problem is I'm not familiar with air brake system-ie: don't know where brake switch is located.
Great to be on forum and thanks in advance.

[RickO]

Hey Hayfarmer... welcome to the forum! I don't think I have an answer to your questions but one of our experts is sure to chime in soon.

Congrats on your new rig too!

[hayfarmer]

Thanks RickO