Welcome Pike. BCS set up for towing our Monterey at delivery prep, so I’m not sure if our air connection was factory or their addition (see photo 1). Yes they were supposed to be factory prepped, but up to what point? So that could be an accessory connector on an air manifold somewhere under the coach. My hose line isn’t blue like most are, so it’s hard to follow forward from the bumper. It’s black and snakes among wire and hose bundles into oblivion under the bedroom hatch.
The associated electric line with “bullet” connector I think was added by BCS when they set up the tow apparatus; a small red lamp on the dash illuminates to let me know whenever the toad’s brakes are applied. I assume they connected it to the toad’s brake pedal switch.
If you don’t have a bumper mounted connector, hopefully someone here knows where to fit a 1/4” airline to under the rig. I can see blue lines in one large bundle of wires and hoses under the bedroom hatch, likely going to the air chuck and tank drains on the bracket behind the battery bay door. Conceivably one could tap the chuck line for the tow setup, but that may not be the optimal choice. If we are factory prepped, then there should be relatively easy access to purposeful air. One diagram I have shows a “tow car brake” line coming from a “service brake relay - ABS” module near the rear (secondary) air tank.
Joel