Temp sensor for coolant fan 2014 Chevy Silverado 4.3.

[John jr]

Temp sensor 14  Silverado 4.3...replaced sensor twice..fan will go to full speed and stay on after truck is off.. disconnected battery and it will work normal for a while and do the same thing AGAIN...so aggravating.. anyone else

Edited September 23, 2022 by John jr
shorten title

[Westland]

While I have the 5.3, I have had this issue before and have it again today.  Usually this is the case...  If the engine temp does not reach a particular temp within an allotted time after start up, it will command the fans to run on high.  This leads to two possibilities.  The temp sensor is faulty or the thermostat is stuck open.  Last time my truck did this it was my thermostat.  You can test the temp sensor without pulling it from the engine.  You'll need a multi meter, remove its plug and test resistance across its leads. 

 

My trucks temp gauge shows the increasing temp until suddenly the needle drops to 0 and the fans turn on.  This does not rule out the sensor however.  Awhile back I found a site that has some basic values for what resistance the sensor should read and it ruled out my sensor.  Below is a link to it.  It is possible it isn't reading correctly for me this time.  I plan on checking resistance once the engine cools down. 

https://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/how-to-test-the-coolant-temp-sensor-1

 

If you've replaced this sensor twice then most signs point to the thermostat.  However, the AC pressure sensor will also cause the fans to run high if it has failed.  I haven't read of it happening often. 

Edited October 19, 2022 by Westland

[Westland]

My temp sensor ohm'd out within range (80F - 2500 ohms).  Got a new thermostat and replaced.  I could blow through the old thermostat housing and thermostat itself was visibly cocked.  Thank goodness these fail open rather than closed.  I removed the negative battery cable for a moment to reset things and fired it up.  Problem solved.  A little concerned that the previous thermostat was just over a year old though. 

 

The thermostat with housing was around $50.  Hope this helps your issue.