Hey whats up! The other day I was tightening the passenger's side header on my car due to a leak when I discovered what appears to be a 2nd knock sensor! Its located under the 2nd primary towards the back! or is it a knock sensor? I know that the other sensor is lcated in between the 1st and 2nd primary which is easy to access. Do I happen to have a different type of engine or something??

Thanks,
Ruben

 

Sounds like the temp switch used to turn the fan on.

 

I thought that was the dash temp sending unit?

 

The knock sensor is down low next to the oil pan rail and installed in an existing block coolant drain plug hole.

The dash temp gauge sensor is installed in the drivers side head. Electric cooling fan cars will have another temp sensor installed in the passenger side head. The ECM temp sensor is usually installed in the thermostat housing or intake coolant runner.

 

The ECM turns one fan on, the switch in the passenger head turns on the other one.

 

Oh so thats what that is ! Looked like another knock sensor to me but now I know what they are! Hey I appreciate the info guys!

Thanks!