93 7.5l engine coolant temp sensor
 

I have a rough idle I'm trying to figure out. It is really rough when cold and the high idle only lasts for about 20 to 30 seconds tops or stops immediately when I turn on defrost or vent controls. (vacuum leak?) When it's warm the idle is a little rough in my opinion but that's for another day. I want to test my ect sensor can anyone tell me where it's at and what the ohm values should be?