LS 5.3 Drive By Wire ~ Stand Alone Wiring Harness (TAC I'm simplifying a factory LS 5.3 Drive by Wire harness for stand alone service. The question I have is how to wire the Throttle Actuator Control (TAC) Module Stop Lamp In (STP LP IN) wire Light Blue (LT BLU) pin 6. From the schematic I have (posted pics below), I'm thinking Ignition Power (On - Start 12 VDC) is sent to the TAC Module when the brake pedal is depressed? Drive by Wire Vortec 4L60e Stand Alone LS Swap Harness Our harnesses are designed for installing these new GM EFI engines into your ride, whatever it may be. This harness is specific for 2003-2007 4.8, 5.3, and 6.0 Vortec engines with RPO Codes LR4, LM7, L59, LM4, LQ4, and LQ9 with a Drive by Wire (Electronic) Throttle Body with Multec Injectors.