Mine didn't have the electrical disconnect solenoid like that, and I think the pin is a manual alternative / backup solution.  I do think one or the other is necessary when trying to backup a loaded trailer without activating the trailer brakes.

On Sun, Jul 23, 2023 at 8:56 AM Mark Whipple <mark at whipplefamily.com> wrote:

> My surge brakes have an electrical disconnect for backing up. It's wired to
> the backup lights on my vehicle.
>
> Mark
>
>
> On Sun, Jul 23, 2023, 7:41 AM Olivier Hecht <oehecht at gmail.com> wrote:
>
> > There should be a small pin that goes in a hole across the tongue to
> > prevent the sliding action that activates the brakes when you need to
> back
> > up. If you don’t have that pin, you can look for the hole that should be
> > there and get the correct sized pin for it. You still have to insert it
> > each time you need to back up, but it’s easier and better than
> > disconnecting the line.
> >
> > On Sun, Jul 23, 2023 at 7:23 AM Scott Andrews via Rhodes22-list <
> > rhodes22-list at rhodes22.org> wrote:
> >
> > > I am unable to back up without disconnecting the brake line quick
> > > disconnect.
> > >
> > > Sent from my iPhone
> > >
> > > > On Jul 22, 2023, at 4:17 PM, Ric Stott <ric at stottarchitecture.com>
> > > wrote:
> > > >
> > > > Umm - What?
> > > >
> > > > Sent from my iPhone
> > > >
> > > >> On Jul 22, 2023, at 5:18 PM, Jeff Smith Photo <
> > jeffsmithphoto at gmail.com>
> > > wrote:
> > > >>
> > > >> Has any one had air introduced in the brake lined by decoupling to
> > > extend
> > > >> the tongue?
> > > >>
> > > >> Best Regards
> > > >> Jeff Smith
> > > >> www.http://JeffSmithPhoto.Net
> > > >> 732-236-1368
> > >
> > >
> >
>