(05-11-2019, 08:16 PM)Black Aeronaut Wrote: That's what a five-flat connector is for - it's just like a four-flat, only with a fifth wire. The fifth wire uses the current from the reverse lights to activate a solenoid valve that cuts out the brake. The solenoid valve is designed so its failure mode is in the open position - this way, while it's annoying as hell when it breaks, it at least doesn't prevent the brakes from activating.
I'm kinda surprised that not all surge brake systems use this.
30 cents of wire and a 35 cent solenoid, that's why. Cut the price, yet maintain the profitability, while selling to people who don't know what they're missing and blame the surge brake instead of the cost cutting, and then buy the higher profitability trailer with the simpler system.
"You know how parents tell you everything's going to fine, but you know they're lying to make you feel better? Everything's going to be fine." - The Doctor