It started out that my gauges worked. But when I turned the lights on my oil pressure and Temp gauge would get messed up. I checked under dash for ground issues. Sure enough someone added these gauges or worked on them before. The metal tab off headlight switch was not hooked up and ground to Speedo cluster was disconnected. I put grounds back in place and now lights work great. BUT gauges are not working. So frustrating. Thought the grounds would fix it. Pins on circuit board are nice and tight. Verified all wiring is correct. Stumped. Considering new gauge from the Parts place. Thoughts??

 

I would start by pulling the gauge pod out of the dash and bench testing it.

 

Can you tell me the process of doing that. What am I looking for on gauge readings. Etc…???

 

Ground the case
Connect 12 volts to the ignition circuit (pink wire in the connector)
Connect ground to the sending unit wires (green wire for the temp gauge, blue wire for the oil pressure gauge, tan wire for the fuel gauge)
You can also connect 12 volts to the grey wire terminal to test the dash lights

You should see each gauge needle sweep the full length of the gauge face when you connect the sending unit terminal to ground.

 

I’ve done that. Gauge is out of car. Needles respond as you said but with all wires disconnected the needles don’t rest at 0. I’ll do as you say again and make sure connections are good. Thank You.

 

When the gauge is disconnected totally from power, the needles rest near where they were when the car was shut off. They will not zero out like a modern car when you turn off the key. Are you saying you removed the sending unit wires from ground, and the gauges did not zero? Or are you saying that you removed all the wires including 12 volt ignition and the case ground when the gauges did not zero?

The photos below show an original 68 ralley pack