Im looking through my engine bay tonight and I noticed this broken wire. I didnt have a good flashlight to trace it but it looks like its coming from that sensor in the thermostat housing. What is this?

 

If it's the plug that you are pointing to, then that is the air pump connector. If not, then is the plug behind the thermostat?

 

in the closeup, it shows the grey connector sitting on top of the smog pump. This plug has two wires. One of the wires, the broken one, looks like it runs to the thermostat housing. I really couldnt see very well because my maglight vanished and I was stuck with a dim toy flashlight.

 

That looks like the smog pump clutch connector. Both of those wires should go towards the wiring harness. Without your smog pump, you'll have a tough time passing an emissions inspection.

 

So that explains why my car's exhaust fumes started to smell real bad all of a sudden. Thanks

 

UPDATE: I fixed the broken wire and now my exhaust fumes smell like the day I bought it! No more teary eyes and stinky clothes when standing behind the car for a while.