Orange wire connector under intake

Anything that is that color on a Prius is high voltage, and it works by not having you touch it, unless you have first pulled the high-voltage safety plug from the back of the car, and waited ten minutes for stored charges to bleed off.

From your description as "under intake", I'm going to say it's the high-voltage power to the air conditioner.

Why the interest?

 

This is the plugs you have to pull the insert out make it pull out then pushing the plug will come apart it can easily be broken you should watch a video or look at an instructions carefully because the first one of these you do not knowing how to do it lot of people break them which doesn't make anything happen they still go back together they just don't lock properly. And that may be important I have unplugged my air conditioner many times without unplugging the safety plug at the battery when I was having air conditioner troubles as long as you set the plug down and nothing goes up into the live end like a screwdriver blade the end of a long screw whatever it is safer to pull the orange plug but if you're just unplugging a compressor and plugging up another one if the car is off and not ready you should be good. But like Chapman said if you don't know how to take that plug apart you should probably initially be taking the orange plug out DC volts will kill you quick they're no joke