Coolant Temp Gauge Inop...

[ej2003f250]

Hello, and thanks in advance for the advice...
Here's the story, I just bought a 2002 f350 the temp gauge hasnt worked in it since I bought it. I have read a lot of the other threads on this subject and have done the following...

I've replaced the coolant temp sensor (near the thermostat) with both of the ones that I could find for this truck

I've done the gauge self check and the gauges all do their sweep
When I turn the key on the guage jumps up to its starting point but never moves past that.

I have also tried to jump the harness, by connecting the two sides with a short wire... I'm assuming that that's how its done.

I currently have the gauges sitting on my lap and I'm just wondering if there anything that I can do to check the cluster itself.

Also Ive read on here that theres a chance that the thermostat could be bad. That being said I'm afraid to replace it and the coolant with out the gauge working for obvious over heating reasons and not being able to tell if it is.

Thanks again for any advise, I can use it!