Sound of pump at start-up

[jpalmer1717]

So I came across two plugs (see attached pic...located to left of dipstick) with one that looked to be intentionally disconnected. Can anyone tell me what it's for. I plugged it in and I now hear a small motor running after startup. Not sure what that is but it's new.

[Ccmano]

Those are the AC temp and pressure sensors. Pump is probably the air injection pump for emissions. Turns off after a few minutes. The pump is located driver side ahead of the wheel well next to the radiator. The pump and sensors are not related.
H

[jpalmer1717]

Great, thanks!!!