help with my panel cluster

[JoeKan]

I'm getting around to working on my panel for my 68 IH Travelall. Only one of the four instrument gauges is working. It's the alternator. The gas gauge doesn't work because I'm still working on the gas tank. How can I tell if the other gauges are any good? I've search and looked at youtube, but everything is still as clear as mud.
Any help will be appreciated.
Thanks!!
Joe

[VetteVet]

Most gauge clusters use a fused, key on, power source from the fuse panel, and they complete the circuit to ground through a sender unit. Temperature and oil being two. some of them are mechanically actuated, such as the tach and speedometer and certain oil pressure gauges. Most tachs are electrical and are wired to a power source and to the negative side of the ignition coil.

I'm not familiar with the International trucks but if a wiring diagram were available it would help.
Usually if you ground the temperature gauge wire to the block with the key on,the gauge will go to full hot.
The fuel guage wire if grounded with the key on will usually go to empty

If the oil pressure gauge is mechanical it should read when the engine is running.

Your best bet would be to get a manual for the truck and use that.

[JoeKan]

Ok, sounds good and thank you. I appreciate the help.