I have a 2005 Excursion - basically the same thing. I'm not sure what you're asking - where are the air brakes.
The brake peddle is down at your feet at the base of the steering column. The brakes themselves are located on each wheel. The air tanks (on the 2005) are located back behind the generator. The cables to drain them are on frame rail to the right of generator. The air dryer is on the left side back by the rear axle. The knob to activate the air parking brake is below the dash to the left of the steering column.
Also, call Fleetwood, they're good at answering your questions.
And when you have a question like this, don't sign off and disappear right away. Two people came back quickly with answers even though we don't really understand your question. You could have provided clarification and had better answers by now.
Bill