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CTS and IAT normal resistance readings?

S

sjkolodz

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Location
baltimore, MD
I'm doing some basic checking of a 1995 6.6 L. I tested resistance of both CTS (at coolant crossover pipe) and IAT sensors with digital meter, engine cold, about 65F. Removed connector and touched both sensor pins. There was no reading or "OL". Engine warmed up (15 min) and read CTS of about 250 ohms; very close to chart values. IAT was still reading OL. Bought a CTS and ohmed it out of the box; it read OL. Store did not have IAT in stock so I didn't get it. All info on forums state these are temperature dependent. Are they really temp dependent, are they on/off at a set temp, did I get a bad CTS or something else? Thanks.
 
I went away for the long weekend, but kept thinking about the strange readings. So back to basics. I borrowed a meter from a friend, tested both sensors and values agreed with published charts. I looked closely at my meter and how I was taking readings. I noticed that the wire to the red probe rotated some as it entered the molded head; the black one was solid. I tried my friends leads on my meter and it read correctly. I decided to cut the molded head apart and found that the wire was mostly broken. It appears that it would make or break contact depending on how it was twisted when making a measurement. I bought a new set of leads; problem solved.
 
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