Make the Most of Your Power Stroke's exhaust backpressure valve! BD's BrakeLoc connects to the EBPV control wire, turning the factory valve into an electronically-controlled exhaust brake. Includes the BD AutoLoc to maintain lock-up when the exhaust brake is activated ensuring that 100% of the retarding force is being transferred in 3rd and 4th gears. Note that, because the EBPV is activated hydraulically, there is typically a 2-3 second delay between the time the valve is actuated and engine retarding occurs. While the BrakeLoc is an economical alternative to an exhaust brake, it is NOT intended as a substitute. For quicker, more effective braking, we recommend a BD exhaust brake system, which utilizes our Variable Orifice Technology, and won't stick like the stock EPB valve can.