A couple of questions off the top of my head here.
Are you trying to install an after market gauge with a stock sensor?
Does your gauge require a sensor with a specific output?
Does the factory sensor output match the requirements of the gauge you are using?
Do you get where this is going?
I could be wrong, especially since I don't know what gauge you are using, but as far as I'm aware, tem gauges are calibrated to work with a specific sensor, so unless you're using the correct sensor or you know the sensor and gauge you have match one another, they will not work and you could in fact damage one or the other.