The best way to bench test is to remove the sender
bench test video Remember to ground the sender,cluster,then wire as it is in the truck. sender wire to gauge and power to gauge.
with the sender out you can check it with a meter. mine is 30 ohm
sender check video I will add this about a pinched needle (1950 cluster)
I noticed the new gauge sits higher in the cluster.
needle pic needle pic I made a spacer out of gasket material to keep the bezel from hitting the needle.
you may not need this, try pushing the bezel out a bit.
spacer pic spacer pic pic