I have a 1960 gauge wiring question

[drumyn61]

I have a gauge cluster with dummy lights and I bought a replacement cluster with an actual amp gauge and tach. Can I just cut the bulb wires from the dummy gauge and splice them to the amp gauge?

I did just that and when I turned the key on the amp needle shot to C and when I turned the key off the truck still kept running. I switched the pink wire to the brown wire terminal on the gauge and got the same result.