Does this sound like my Coolant Temp Sensor needs replaced?

[Captain_Ron80]

I've been posting a few questions lately and I appreciate everyones willingness to help. I am just working on cleaning up a few things on the ol' S13 as far as operation goes. Since my blacktop swap my oem temp guage doesn't work properly. When I first started the engine it functioned only once or twice intermittently... Now I get nearly nothing from it. Every once in awhile it will creep up just above the 1st line but that is it. I know it is not the guage because I have 3 clusters and they all have this exact symptom. I am planning on installing aftermarket although I am a bit anal and just want the one in the cluster to work. I have burped the radiator a few times and i'm pretty sure that all the bubbles are gone. A few questions...

1) Does it sound like the coolant temp sensor needs to be replaced?

2) I read that late model blacktops may use a different sensor then early... Confirm?

3) USDM replacement?

Thanks in advance...

Ron