Truck cap brake light wiring

[CamoYeti]

Can anyone tell me the way to wire in the high mount brake light on a truck cap so it doesn't blink with the signal light. It on a 99 f150. Thanks

[masonic]

Did you already try splicing it in but it only works with the signal light?

[Raptor05121]

Put a relay on it and have the trigger coming from the brake pressure switch

[CamoYeti]

I'm really trying not to splice into the tail light wiring I'd like to run it off the trailer wiring if possible. I don't want to expose the important wires to corrosion if possible.