Electrical issue help needed
 

I have a '74 RX-3 that I have been working on. The problem that just came up is with the gauges for the fuel and temp, the other night, the lights for these gauges went out, so the next day I look to see what is going on. Now when I turn the lights one, both the temp and fuel gauge goes to the maximum reading, with the lights off, the work normal. If I remove the bulbs from these gauges, the work fine, until I turn the lights back on. I have taken the gauges out and replaced with a set I got for spare and the same thing , all the lights on the car work fine and nothing has been done on this area. Anyone can direct me at what can be causing this??

No ground or grounding out on metal somewhere.

max reading on the gauges mean no power or voltage to the circuit board.

Thanks for the replys. The gauges were working fine and this happen all of the sudden. I have taken everything I can think of that might be causing this with no luck. What I don't get is that with the bulbs in place and the lights off, the will work just fine, but if the lights are turned on, they go to max and the bulbs will not illuminate at all. Without the bulbs, they will go to max once the ignition switch is on "on" position