I own a motorhome built on a P30 chassis. While doing a tune up i lost my footing and fell into the doghouse. I braced myself on a sensor that screws into the head right above one of the cylinder spark plug holes on what would be the passenger side of the enigne. I broke the connector right off of it. Engine is a 454 Gen V and it has another sensor just like it on the oposite side of the block and both have a single green wire going to them. Can someone tell my what these sensors are and which one i broke?

 

coolant temp sensor???
pull it out and see if antifreeze comes out of the hole

 

It is a coolant temp sensor. However there are two of them and both only have one terminal. I was able to find the temp sensor for the guage however the one for the ECM Ive been having trouble. There doesnt seem to be one that matches. Searching every parts store imaginable both brick and online nobody has it. I think whats going to end up happeneing is im going to have to buy a sensor with two terminals and a new pigtail then run the second wire to ground. Since a single terminal sensor uses the base for ground this should work no problem im just ising a wire instead of the base.

 

are they not the same sensor?

 

I think in this case the proper name for the part is the Coolant Temperature Sender.
I have bought them at AutoZone before for like $7 a pop.

 

The single wire sensor is always for the gauge, The 2 wire sensor is for the computer. They are not interchangeable.

 

Does the 2-wire kind use a type-k thremocouple? I have always wondered that....

 

He mentioned that they are both a single wire application

The only difference between the 2 should be whether it is a positive or negative temperature coefficient

 

Im guessing it would be negitive. When i short the gage wire to ground it shoots to max temp and when i short the other to ground the electric fan kicks on.

 

Looking around i saw that the ECM temp sensor is by the thermostat. So of the two one is for the dash gage and the other is simply used to turn on the electric fan. However i have yet to find anyone that has it......