What sensor is this?

Discussion in 'Chevy C/K Truck Forum' started by kipper667, May 6, 2013.

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  1. kipper667

    kipper667 New Member

    I'm changing the intake manifold gasket on a 1997 1500 extended cab with a Vortec 5.7ltr. While disconnecting...everything... I noticed a broken sensor. The sensor's location is drivers side, above the exhaust manifold, between the #1 & #3 spark plugs. It has a single purple wire that runs to a plug near the intake. It screws directly into the block. I'm guessing it is some sort of temperature sensor but can not find any info on it. Any ideas?
  2. Pikey

    Pikey Moderator Staff Member 1000 Posts 100 Posts

    A picture would help identify it. But, from what you are describing it sounds like the coolant temp sensor. At least that is where mine is located on my 5.3L
  3. Conlan Rose

    Conlan Rose Super Moderator 1000 Posts 100 Posts

    I have the same engine. I believe it is labeled as the ECM temp input/fan temp input.
  4. kipper667

    kipper667 New Member

    I couldn't find any ECM temp but I did find a Temperature switch. This looks like it. Here's a link to the part. I just want to make sure. http://tinyurl.com/cd7zwdx
  5. Conlan Rose

    Conlan Rose Super Moderator 1000 Posts 100 Posts

    Yup thats it. It is one of three possible temp senders on this gen of truck. There is also one below the Thermostat housing and if the truck as an aux cooling fan one on the other side of the block in an identical place.

    LOcation of the sensor I think your talking about which is a temp gauge sender
    2011-06-14_12-06-13_822(3)f.jpg

    Location of second temp sender for ECM and such.
    2012-08-22_19-18-35_11 (1)hh.JPG

    Location of possible aux sender for optional aux cooling fan. I personally don't have one.
    2012-10-13_19-51-29_892.jpg

    Diagram of the aux sender
    engine-coolant-fan-auxiliary-tc0105501.png
  6. kipper667

    kipper667 New Member

    Cook thanks. I was pretty sure but just wanted a second opinion. The whole cooling system was, for the lack of a better word, "jacked up". Replaced the water pump, both hoses, upper sensor (it was broken & glued together), lower sensor connection was broken & the rubber boot was slid back over it (I'd guess to hide it) & the intake manifold gasket was spewing coolant, like a natural water spring, out from between the valve cover & intake. I did a compression test to ensure that the head gaskets were good. Luckily there was a secondary temp gage installed from previous owner. It used to have a plow on it from the looks of all the horrible wiring & switches. Thanks again guys!

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