Using individual voltage reducer 12v to 6 my '52 F1 gauges . If a reducer fails and there is no voltage going thru the gauges no problem.
If the voltage reducer fails and you are now getting 12 v at the gauge will the gauge be damaged? How about the senders?
Any opinion
Is there any way to test those items????

 

Are you using Runtz-type solid state voltage regulators, or plain resistors? Either way, if they fail, they're almost certainly going to kill all power to the gauge.

 

By allowing 12volts to pass thru the gauge, will the gauge be damaged or ruined?

 

I am using individual solid state[

 

Ross is correct. If they fail your gauges will just quit working. In various cars in the 70s and 80s Ford used an voltage regulator they refered to as an IVR. If they failed the gauges would just jump to full scale and then settle back down again. I doubt you will have any problems with the gauges getting a full 12 volts.