I have a complete MaxBrake set-up with the GM plumbing tee. Bought it a few years ago and installed into my '06 Duramax. Plugged my trailer in and the control box did not work with the trailer connected. Sent it back to MaxBrake and they repaired it. In the mean time I had bought a P3 as I needed to tow that weekend. Received the MaxBrake back, plugged it in to confirm it worked, and then put it on the shelf. Fact is, I don't tow much, and the P3 worked fine for my boat. Uninstalled the pressure sensor this summer and have everything on the shelf, needing a new home. Make an offer. Thanks.