1991 hiace temp gauge issues

Hi all, as stated I'm having issues with my temp sensor on my 1991 Toyota HiAce. 2rz 125R . after 5 or so minutes off the engine running (as soon as the coolant warms up) my temp gauge climbs all the way to the top. I grounded the wire to metal and it jumped up to the top I thought okay, I will just get a new sensor. New sensor in same thing is happening.

I thought maybe a short circuit , I pulled put the instrument cluster and tested for continuity on the circuit with an ohmmeter, there's continuity.

Now I'm wondering a few things, do I test if the gauge itself is functional, if so how? I've already tested all the circuits in relation to the operation off the gauge Or should I just assume its broken and get a new instrument cluster/aftermarket gauge. There's no obvious erosion or anything that clearly looks wrong with the back off the instrument cluster.

Hi - stating the obvious - but are you sure the engine isn't overheating?


Here's the resistance values for the sender and the gauge from the manual. That may help identify if it's the gauge or the sender.