So far searches have come up empty.

Has anybody successfully installed a brake controller on a

switch which showed 0V w hen no pushing the brake pedal, and 12V when I push on the pedal.

but the brake controller is giving me an error message saying it’s seeing 12V when it shouldn’t.

My next step is to try the brake wire right at the light. But I’d rather not run another wire all the way back.

Thanks!
Ian

If your car has the tow package installed there should be a grey connector hidden under the carpet forward of the brake pedal.
If not, I'd take the easy way out and find the correct wireless brake controller for the application.

Wireless controllers are laggy and lose connection. I have driven behind an obviously flaky wireless controller trailer and it was a hazard to other drivers. Wired only for me.

Tekonsha has diagrams to help. Even if you don’t have a Tekonsha controller, have a look through their docs to get ideas for your controller. What brand and model controller are you using?