Hi, I was working on my instrument cluster and the left-side "dummy" gauges (voltage and oil pressure) stopped working, that is, when I turn the key to ACC they don't illuminate as they should. The voltage light was very dim at first and then died completely. Might anyone have an idea, please, why this might have happened or where I should look? Specifically, what fuse controls these lights or where are they grounded from? Thanks! The bulbs are not burned out, and the other gauges and lights work fine. It's a 1972, base model gauges, no upgrades.