1996 b2500 5.9 hard start cold; easy hot

[alloro]

Some code readers will display what various sensors are reading while the engine is running. Using such a reader, you could see what it's reading for the coolant temp and compare it to your dash gauge. It's not an exact science but if the two temperature reading were in the ballpark to one another, you could safely assume the CTS was good.

Another method would be to disconnect the plug from the PCM (engine cold) and take an ohm reading on the wires running to the CTS. Plug the PCM back in, run the engine up to temp, then turn it off, disconnect the PCM plug again, and take another ohm reading to compare the results.

Yes it's possible to have a new part go bad. It's happened to me more often than I'd care to count.

[Tommy2500]

Interesting approaches to checking coolant temp. sensor. I don't have a code reader like you do, and hesitate to mess with PCM. I have found that the problem is intermittant; leads me to believe a bad wire, ground, or connector. And, I'll probably
just go ahead and replace the temp. sensor because I've decided to replace the radiator hoses,thermostat, coolant, coil, plugs and wires, and valve cover gaskets. If
the crank sensor isn't too pricey, it'll get replaced too. Gotta throw a few hundred
bucks and couple days work at these vehicles every couple years, instead of the monthly payment for a new one, eh? Later. Thanks.

[Tommy2500]

Just a quick note to this thread; the Van finally decided
to throw me a check engine light. OBD code said 117 - temp.
sensor low output. So it WAS the 2-wire temp. sensor (hidden
in the toughest location on the engine!) that was the culprit
all the time. It just took a while for the thing to get bad enough
to show a code. What a pain-in-the-rump to change.....But glad
we persevered. All fixed now; waiting for the next catastrophe....