Temperature gauge Reading Cool

[coolrunnings]

My 1991 T25 DOKA with a 2.1DJ has always run with the temp gauge in the middle of the gauge (12 o clock) or slightly towards 1 o clock.

Now it reads at about 10 o clock and even sat in traffic a few weeks back on a warm day when the fan came on the radiator it wasn't much above this.

Is this the sensor in the thermostat housing that's a likely candidate?

[ChrisTriple]

I'd say look, at the thermostat.

[MidLifeCrisis]

I wonder if the voltage regulator on the back of the dash has given up in some way.
I'd be checking that there is a nice 10V on the pin on the back of the temp gauge;
One pin should have 10v on it
One pin should be a good ground
Last pin should be some level of resistance to ground (Which is the temp sensor wire)

Have you noticed any change in your fuel gauge operation (that's the only other thing that uses the 10v supply)