Rear disc brakes are inctalled and i love it, bolted right up,
but it came with a new proportioning valve and the sensor in the top is different it had one wire and the old one has 2 wires, any guesses?

 

Yeah....the single wire is meant to ground through the PV's mount, the other does not and grounds through the second wire.

What do YOU think?

Btw, whose system or kit did you use? TSM? Cost? Pics?

 

Minor correction: both the factory and aftermarket proportioning valves turn the warning light on by grounding to the frame through their mounts, but the factory valve is a little more elegant. The left side of this wiring diagram may help clarify: http://fordification.net/tech/images...aster_3of9.jpg

The reason for two wires is for the prove-out mechanism in the ignition switch. When you turn the key toward START, the BRAKE light in the dash is supposed to briefly light up to let you know the bulb is good (and can light up to alert you of a braking failure) before you start driving. Otherwise you'd have to wait for an actual braking failure to know if the bulb worked or not. For added safety, the system is designed such that the prove-out mechanism will NOT light up the bulb if the proportioning valve switch is disconnected.

The proper way to install the two-wire warning connector to the single connector on your new switch is to tie both PURPLE with WHITE stripe wires coming from the truck together, and then tie that single connection to the new switch. This will retain the warning light functionality and the prove-out mechanism. The only thing you lose is the truck's ability to keep the prove-out circuit from turning the light ON if the connector is disconnected. In other words, the BRAKE light will still come ON during prove-out telling you the system is okay, even if it's actually disconnected. That doesn't matter so long as the connector never accidentally comes off. But most people don't pay attention to the prove-out mechanism anyway, let alone even know it exists.