Toss it, not ALL accelerometer based controllers work "perfectly"..
In fact instead of wasting more money on a P2/P3 perhaps you should consider a REAL brake controller called Directlink which interfaces DIRECTLY with your vehicles computer via the OBDII diagnostics port.
Directlink is a fully proportional controller which does not depend on accelerometers nor other trickery, smoke and mirrors or black magic. Instead it reads the diagnostic port data which includes braking info from the vehicle and outputs a proportional brake voltage. Basically it will be as if you have a vehicle which has a IBC (Integrated Brake Control) and will work with your ABS and towing stability control systems (if equipped).
At $325 it IS expensive but it should bypass all those weird problems you are having once and for all..
You can find details on it
HERE"No longer worry about the hassle of finding the right tee or bleeding the tow vehicle's brakes. The DirecLink does not have to tee into the tow vehicle's master cylinder, just plug straight into the tow vehicle's OBII sensor (diagram below). The DirecLink will automatically search for that vehicles optimized configuration and will provide an algorithium that provides the superior braking every seasoned tower has come to expect.
Works with 1997 to Present Ford, GM, and Chrysler Trucks, Vans, and SUVs. 2008 to Present Nissan and Toyota Trucks, Vans, and SUVs."
While I have not tried the Directlink controller I have in several of my vehicles a Jordan Ultimata 2020 which uses a steel cable that attached to the brake pedal. Unfortunately Jordan was bought out and put out of business.
I now have a 2013 F250 with IBC, and am very pleased with it, it feels and works as smooth as my Jordans.
I think you will find the Directlink a vast upgrade over any accelerometer type controllers..
