Temp gauge issues

[ScooterBJ]

Since the weatHer has turned cold I have noticed issues with the temperature gauge on my '09 500. At first it would take a long time to register. Then it would not register until tapped firmly (could be coincidental) and the. It would start working. On a ride of about 5 miles couple days back, it did not work at all. Tapping did not help.

Has anyone else seen this happen or have an idea of what might be going on. One concern is if the temp sensor is behind, rather than in front of, the thermostat. If the temp gauge is behind the t-stat, then hot coolant is not circulating.

Any ideas???

[ts1]

The sensor is behind the thermostat in the big circuit.
It takes some miles to warm up the small circuit and suddenly the needle rises.
If not, check the expansion tank under left floorboard.

[ScooterBJ]

Thanks TS1. I'll check that out. I figure on stripping off a bunch of the body panels for some other work soon, so it is a good time to get into this.