I just bought a used 1995 blazer. The temperature gaugefluctuates so rapidly that it appears to be spinning in circles. I was advised that this is probably due to a bad temperature sending unit. I went to Autozone and bought both the coolant temperature sensor and a temperature switch. What I need to know is:

Which one of these is likely the culprit?
Where is it located?

Thanks,
Mark

 

It is possible that the sending unit is at fault, but I would first disconnect the wire to the sending unit and make sure that it does not touch anything. Then observe the gauge. If it still jumps all over the place, then it could either be a faulty gauge or a wiring issue.

 

I thought I knew where the temp sending unit was, but when I disconnected the wire. The connector didn't look anything like the connector on the new one. So I'm thinking I disconnected something else. I thought it was on the passenger side of the engine, right above the spark plugs.Is this correct? Does anyone have a diagram or schematic?

Thanks,
Mark

 

Temp sensor for the gauge is on the drivers side of engine and is located right above the knock sensor. the knock sensor as a 1 wire connector going to it the temp sensor has a 2 wire connector it is right above where the #3 spark plug is

 

It appears that the coolant temperature sensor (which goes to the computer) is located on the driver's side above the #3 plug. I still can't figure out where the temperature switch (which goes to the gage) is located.

 

why do you think that? I'm reasonably sure that is the gauge sender. Ground it out and see if the gauge pegs. Of course that is not conclusive if nothing happens but I believe that the gauge will move.(peg at 260). Jerry-you know what, now that I think about it, look on the passenger side of the block, at spark plug/water jacket level. Seems to me that is where it was on the last one I did. Good luck-let us know!

 

You guys are right! That is where the temp sending unit is located. On the driver's side, above the knock sensor, right above the #3 spark plug. And I'm sure it's the problem. The reason I had so much trouble locating it, is because the connector was broken off the sending unit, but was still attached to the wire. The wire had bounced aside. I will change it out this weekend, when I have more daylight and it's a bit warmer.

Thank you guys!
Mark

 

http://i559.photobucket.com/albums/ss33/dljr82/43L.jpg

Hopefully this helps.