Mystery wire
 

Hello
Thanks in Advance for all your help. I recently took my jetta 1.8 to a mechanic for an oil leak. Got the car back, did some quick inspections, and found this wire disconnected. But I just can't find where or what It connects to. The wire starts somewhere at the drivers side headlight, and runs accross the top of the radiator and just stops. I can't go back to the mechanic, because of a well merited argument we had....Please help!