[hypoxia]

Jim,

That supplies the rear air chuck; necessary for the Air Force One supplemental/emergency brake system for the TOAD. After the last few years of severe tow problems? I feel the AF1 (or similar) is a mandatory piece of safety equipment.

That said…On my era of coach (2015), Newell wired the power that feeds the 7-pin to ONLY BE ACTIVATED when that Trailer Brake is CHARGED and the Parking Brake is disengaged. Otherwise, you’ll have NO brake/turn signals back there!

This caused me a case of lost hair until I talked to a tech at Newell. Dumb…and the bad thing is, I haven’t met a single other coach owner who’s aware of this configuration, let alone remember to plunge the trailer brake when they Tow!

So, I’m gathering you don’t use the AF1, but if you do…then not only is that rear air chuck dead, but my guess is your 7-pin (at least the brake/signal leads) will be as well.

Let us know!

That air chuck is dead, I will check the lighting, fairly sure it works.  Here's what the rear air tank feeds on the red engine, unidentified so far.