Constant voltage on blue trailer brake wire

[Pedro_The_Swift]

No ignition, not connected to van, constant 4.6v at the blue wire at the trailer plug. All wiring tests ok for continuity to earth and between wires. I have disconnected my tekonsha and this problem is with the backup Redarc. I have no idea how or where the wire is connected to the brake switch. I get the normal red glow from the small pilot lamp when the brake pedal is pushed.
Is this a normal redarc thing?

[W&KO]

The redarc towpro doesn’t like being tapped into the brake switch circuit.....

I found its best to tap into the brake light wiring at the plug

Not sure if that will assist your problem.

[Pedro_The_Swift]

I'd really happy to find that connection..... but its not likely.. mines not a tow pro,, it has a little red knob that varies the constant voltage thats applied when the brakes are used. Its not as good as the tekonsha,,, But i need something to get me down Blackbutt and Peachester ranges