[Nickosport]

Does it operate correctly otherwise, like when driving around normally? All of the other guages work?

The tach on these cars is run off the canbus, a stepper motor operates the needle. As you say, it should sweep when you turn the key.

My suspicion is that there is a problem with the cluster. The ECM must have a good rpm signal if the car runs without throwing a code, so the issue is somewhere in the cluster. Its not a communication issue with the cluster, as the ECU would throw a fault code if that was the case.

First thing i would do is disconnect the battery, hit the brake, then reconnect the battery and see if that solves the problem