trouble with temp guage

[nturner]

I'm having trouble getting my temp guage to work on my 72 Cheyenne. Brand new cluster and new 350/330hp crate motor. The hole for the sensor on the new motor is smaller than the stock motor so we need a new sensor. The old stock sensor shows 45 ohm so we need a new one the same with 45 ohm resistance with 5/8 threads. So, when we hook everything up, we get zilch. Does anyone have a wiring diagram of this circuit ( could also use a diagram of the a/c circuit ) or have a clue as to what we may be overlooking?? Thanks