I have 09 f150,I want to wire a cap with a high mount brake light.
Where do I connect to ?.
I have tried the tail lamps, but the light flashes with the turn signal,same thing when I wire into the trailer plug wires.
Is there a chmsl wire tucked away somewhere just for this purpose ??
THanks Al

 

what the #$%^ is a chmsl?

 

It's the Center High Mount Stop Light (CHMSL) or the third brake light at the top of the cap..

 

that is how most people wire them these days, just tapping into the brake wire, yes it will blink, i know for a fact that is how the local shops installs toppers. i would think that you could tap into the brake pedal switch to get your power from, then it would just work with the brake pedal, but you would need to run a wire from under the dash to the topper obviously.