It's typically what's used for power on a timing light. BTW thanks for the write-ups guys. I think this will be useful info.

 

Hmmm having issues with mine right now after 10k km and over a year of flawless operating...

Mine's powered off the radio supply(as I have no radio), grounded at the intake manifold (and using a second ground at the head..which I'm going to change now) Sensor was 2-3 inches from the turbo but is now 6-8in downstream.