Temp Guage issues

It appears to me that gauge indeed has an internal limiter.

The 12V terminal would be fed from the ign switch, and the "item" is a condenser/ capacitor and is there to supress radio noise/ static.

It appears the limiter is IN the gauge, and the 5V terminal would be to feed OUT from the limiter to the other gauge(s) such as fuel, oil, anything using a sender.