How can I verify the wiring to my coolant temp sensor is working properly?

 

Obtain a rheostat of approximately 2KΩ.

Remove the connection at the CTS.

Connect the rheostat from the wire to ground.

Adjust the rheostat back and forth.

If your wiring is OK you will observe the temperature indicating full hot to full cold.

 

It's a two wire connector.. there is nothing to observe the temp going from hot to cold on.. I don't have a scan tool..

 

.... why, fan not switching on?

 

Fan not switching on and a nice bog off idle, I had the same problem not long ago and a new CTS fixed it up.. the only thing I've done since than is replace the intake gaskets due to a leak at the rear china wall.. since putting it back togather my problem is back. The voltage at A + B with the sensor disconnected is 5.17vdc. With the sensor connected it does slowly go down but not enough, at roughly 240 degrees it shows a voltage of 1.20 vdc... can anyone point me in the right direction???

 

Unplug the ECM and do a continuity test from the connector pins to the ECM

Reference
http://chevythunder.com/

 

will do, C10 is the yellow wire according to that link, which is the black wire? Or does the black wire simply go to ground somewhere?

 

Well I tested c10 from the pcm harness end to the connector end at the sensor, .4 ohms on the 200 ohm scale. What should this wire ohm out at? I just looked at the provided link again, I see that b6 is the ground.. I'll check that tomorrow..

 

.4 ohms is barely anything. That means the signal wire is not your problem
If your ground comes back similar resistance (0-1 ohms) then wiring is out of the picture

 

so basically if the ground checks out I'm left with the ecu? Or 2 bad cts's..

 

22 guage stranded wire is typical .01495 ohms per foot, 8ft would be less then .12 ohm. 1 ohm would be way to high for even a 25ft length of 22 guage wire.

 

so are you saying I do potentially have a wiring problem? What range would be considered "good"?
On another note does anyone know how the test the cts with corrosponding voltage values for temps with the wires connected?
Is there a way to test just the sensor itself with out the wires hooked up via ohm meter?

 

Well I'm guessing its my pcm/ecu... both wires ohm out exactly the same at .4 ohms, source voltage is sometimes 5v on the dot and sometimes its 5.6 or higher.. when watching the voltage readings as the car heated up they started at 2, slowly went down and when they were about to go to below 1v they suddenly jumped to over 3.5v and started going up.. same thing with 3 diff cts's I had laying around.. I guess I'll be making a trip to the boneyard to grab a pcm.. anyone know what years and models of cars are compatable? Does it have to be from a tpi car? I'm assuming its p/n #1227165.. are there any other p/n's that will work?