You would have to purchase the entire switch as far as I can see. That may run about $70-$130.
Then, the bulb casings, $30-$50/each, the dam, $90, the bulbs, $17/each, the harnesses, $15/each, the wires from the harness to the light switch, $45. It might very well get pricey.
I'm just estimating based on the crap I've seen GM pull in the past.
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