Dash temp gauge failure

[grampakoot]

1998 Allegro Bus with Freightliner Chassis, Cat engine.
Temp gauge not registering at all. Needle sitting on far right of gauge.
Aftermarket gauge installed by others also failed. All else appears to be working well.
Recently had AC compressor replaced at Freightliner dealer. Returning to them today....any advice please?

[OneRVer]

what engine do you have?

[grampakoot]

Cat 3126B
275 HP
Was able to reconnect aftermarket gauge so it now works.
There are two connection hubs on temperature sensor station at motor.
Mechanic says they both appear to be working. His opinion is that either dash gauge itself is faulty or there is a link malfunction somewhere.
I am going to rely on aftermarket gauge until I can resolve the dash one.

[OneRVer]

Yep I know where you are at. I have the 3126 on a 1997 Freightliner. I had to install an after market engine temp gauge and I did not have a reading to my transmission so I went ahead a installed a transmission temperature gauge also. You do not want to know the cost of fixing the OEM gauges.

Is your after market temp sensor installed in the bottom port of the thermostat or the top port?

Do you have a 3126B or 3126? I understood that the 3126B was built after 2000?