It doesn't go to the ECU...
You can catch it on the switch itself, on your upper side of the gear box, red with black strip wire.
Or
If you insist to catch it near the ECU, you should also find it on IG2 connector (20 pin dark gray connector) at pin 13 going from the engine harness to the body harness.
Let me know if you need the schematics for that.