Stand Alone Harness - Purple - Brake Switch (Optional)

Wiring harness instructions

BRAKE SWITCH

1.  PURPLE WIRE

This wire is for Torque Converter lockup operation and in certain applications cruise control disengagement. AC Delco part number D850A is a common universal brake switch that has both normally open (For brake lights) and normally closed (For TCC).

A.    Connect to a brake switch signal that has 12V when the brake pedal is not pressed, and an open circuit when the pedal is pressed. This is the opposite of how the brake lights work.

B.    This signal is not a critical function for the engine to start and run. It is only for torque converter lockup and/or Cruise control disengagement..

C.    If a torque converter fault is present, a scan tool should be able to read whether the ECM is detecting the proper TCC/Brake switch signal by showing the brake switch either “engaged” or “disengaged” when the pedal is at rest or depressed.