T800 brake light pressure switch location

Picked up a new to me T800 Dump truck. It's a 2001 with a 6nz. Wiring and air line work was not the previous owners strong suit. I have been busy re-plumbing air lines and repairing wiring.... or atleats attempts of wiring. I am trying to find the location of the brake light pressure switch so I can tie in a electric brake controller. I never thought it would be so hard to find wiring diagrams. Even the dealer cannot print them for me supposedly.

If anyone can help me out with a location or picture it would be greatly appreciated.

I was under the impression it would be on the inside of the firewall to the right of the instrument cluster. However the switches there either are for the primary and secondary buzzer or have no power to them. Yes the stop lights work on the truck when you step on the pedal.

Thanks in advance

Also if anyone knows where I could find wiring diagrams it would be great.