[66 Stepside C X]

Thank You everyone! I will take another look tonight after work and see if I can locate the fuse box. I’m currently dealing with the aftermarket autometer guages installed. At first I noticed the Voltage gauge gets pegged with the truck on. Then I noticed the light in the oil pressure gauge and temp gauge was very dim. I pulled out the old bulbs and replaced the temp and oil ( very night bright white led) then I noticed the Voltage gauge is not even have a bulb in it, or even a bulb socket. Shown in second picture above. Looks like PO hooked up power from
a yellow wire and then split the power for the bulbs into the three gauges. The strange thing is the bulbs will only light up when the metal socket part touches something else metal also the voltage gauge does have a wire for a bulb but it has a female crimp on to a male spade. Also they have a wire that’s just connected from the volt gauge to the oil pressure gauge and nothing else... maybe that’s supposed to be a ground..
So I am assuming the entire setup is not ground properly. Somehow while messing around with the bulbs I got the Voltage gauge to read proper Voltage. Not sure how. Again any help is greatly appreciated.