Flat Shift Wiring

Nexus Series Firmware Help › Transmission › Flat ShiftUpdated Sep 2026

Before flat shift can do anything, the Haltech Nexus needs to know when you want to shift. That signal comes from a switch, and the Wiring node in NSP is where you tell the ECU which input it's on.

You can use any free AVI (analog voltage input) or SPI for the flat shift switch. Common choices are a clutch switch or a load-sensing switch on the shifter. Pick an input that's free, wire the switch to it, then select that input on this page.

Before your first flat shift, check:

  • The switch changes state in NSP's live data when you press or pull the lever.
  • It reads in the right direction, active when you want to shift and inactive otherwise.
  • There's no flicker at rest. A noisy input means false cuts.

Next, set the cut itself in the flat shift function and Torque Reduction Time. Need the wiring diagram? Ask us and we'll send it over with advice for your build.