Running a LY6 with 4l80E swap. ECM, TCM, harness are all from the same '08 Express van. Brake switch is a combo switch from a mid 80's GM something - brake lights N/O, brake/tcc signal N/C.

It runs/drives great but the scan tool always indicates brakes not applied. TQ lockup works but will not release if the brake pedal is tapped while crusing with the TCC locked up.

Have verified signal works at the ECM and TCM connectors.

Even though the brake signal goes to all 3 modules (ECM,TCM,BCM) could the Express van cal get brake input over CANbus from the BCM? Noticed that the brake switch diags P0719/P0724 are not enabled in the ECM or TCM cal so I'm guessing they are in the BCM.

Any thoughts?