Twitchy coolant gauge issue. Ideas?

[JaredwS]

My coolant gauge is being super twitchy, bouncing all over the place. Coolant level is fine. It does not really do it when the car is idling, only once or twice. When I press the clutch in and the engine rpm drops to idle when I am driving, it generally returns to normal. Any ideas as to what is causing this? Could this be an indicator of a bigger problem? Thanks for the help.

-Jared

[kiko]

Have someone move the plug connected to the coolant temp sender unit while you're looking at the gauge. I had exactly the same issue and it was the connection.

[90///M]

Also check the ground nuts on the back of the cluster. I used to have this issue, I tightened them up and it went away.

[Bryan]

Yea, I had this. It is a grounding issue. It could be one of two things:

1. The ground nuts (tiny little nuts) on the back of the gauge in the cluster
2. It could be the connection at the coolant sensor, or that the wires that go to the sensor are frayed and are grounding on the chassis.

Easiest to check first are the wires. Turn the key to position 2 and have a friend jiggle the wires as they come around the head and to the sensor. If the gauge starts going crazy, or fixes itself, you've found the problem.

[JaredwS]

Thanks guys. I will check these things out.