can someone tell me what the black gadget "circled" in the photo is for.

GREG

 

coolant/water level sensor...and that's also the filler neck/t-stat housing connecting to WP.

 

i supose in an ideal world there should have been a wire connected to it..i see there is a black one nearby, which has been grounded. from previous searches, is this because of the buzzer irritation problem?

Greg

 

"Buzzer irritation problem"? If the car is working right and maintaining proper coolant level, there IS no problem.

Are you saying someone had disconnected yours at some point?
Are you experiencing a loss of coolant or some low-coolant alarm going off all the time?