[pjmoreland]

You're gauges are probably good, but I encountered a temperature gauge once that passed the test you did above, and it was still bad. The needle wouldn't move from C after the engine warmed up. I think there was an internal short in one of the windings that still let it work partially. Because of this, I like to test these gauges by connecting the Sender post to a second 90-Ohm resistor, and then connect the other side of that resistor to ground. In this state, the needle should move to the normal operating temperature position where the needle is approximately 1/8" to the right of the second line.