Yeah, my Pioneer radio has a digital voltmeter display built into it. It's nice.

The Nelson harness will turn the fans on low when the A/C kicks on. I wired my self-dreamed-up harness to run the fans on high with the A/C.

The Nelson harness is already assembled nice and pretty. Both fans run at low speed with the A/C on unless the engine gets too hot and then the PCM commands High fans.

Do you have a Nelson tune already or own HPTuner software so that you can enable the fans in the PCM?