Hi,
I have an 85 GT and I was cleaning up the engine compartment yesterday when I came across an unconnected wire just hanging there under the three vacuum lines just to the right side (viewed from rear of car) of the upper plenum. I searched around and found the other end also just hanging there. If I remember correctly, the first wire I found was green (not sure if it had a stripe or not) and the other wire was white. The other end of the white wire seemed to be connected to some round metal object about the size of a nickel that sits between the thermostat housing and the upper plenum but underneath the three vacuum lines that run through there. I searched through my Hayne's manual hoping for a photo showing all the V6 engine sensors, etc. but could not find a photo of this area that showed this wire or the part it is connected to.

Does anyone have any idea what this is?

Thanks

Here are the three sensors in that area. I think the ECM Temp Sensor has a green wire and white wire.

[This message has been edited by Gall757 (edited 04-24-2017).]

Thanks for the reply. I found a photo and added a circle and arrow to the part that I think this wire was attached to. It had the plastic flexible wire cover around it.
http://s1002.photobucket.co...zpsb76a4b18.jpg.html

Here you go

Appears you are looking at the fan switch. Single wire with a big, rather squishy plastic cover? The fan switch goes to ground when the resistance hits the design value which completes the circuit to the radiator fan. When I first bought my car the PO had just hooked an alligator clip to the wire and permanently grounded the circuit so the fan ran whenever the car was running. Not the approved solution to an overheating problem.

Fan switch image from Rodney Dickman website.
http://rodneydickman.com/ca....php?products_id=349

Cold Start Injector Switch from Advance Auto website.
https://shop.advanceautopar...e+temperature+switch