Hey,
I am working on changing my expansion valve for my AC. On the passenger side defroster vent by the bottom of the front windshield, there is what looks to be some sort of infrared sensor that plugs into something unknown. Do any of you know WTF this is???

 

it a temp sensor for your automatic climate control to mesaure current air temp inside the cabin

 

AHHHHHHHHHHHHHH. thanks.

 

I always wondered what that thing was for

 

read the manual

 

The sensor by the passenger defrost vent is not a temperature sensor but rather a sensor to measure the amount of solar gain (Heat load caused by the sun). This sensor allows the climate control to compensate for bright sunny days vs overcast days. If it didn't exist, you would feel as though the air coming from the ducts was too cold when your car went into the shade such as when driving in the city (building shadows) or driving under trees etc. Most of the heat entering your car on a sunny day is transfered via radiant energy vs conduction. Without this sensor the climate controller would not be as effective at keeping its occupant comfortable. Hope this clears up the issue. I hate mis-information

 

Excellent post by the newbie! Welcome to the org Doug.