coolant gauge issues
Hello everyone. Brand new here, but just purchased my first 3 series.
When I purchased vehicle coolant gauge stayed in cold position at all times.
Replaced coolant gauge sensor last night:
As soon as it was installed and I clicked engine over, temp gauge went pretty fast right up to hot and the warning light came on (about 15 seconds)
Coolant was room temperature and was not hot.
This morning, after the car cooled all night, the temp gauge started at normal and immediately went up to hot.
I did disconnect the wire harness and the gauge did go back down to cold.
Is this problem an issue with the gauge, or is it a faulty ground within the circuit??
Any advice would be much appreciated!