Can you show me your original socket? Is it a 1156 (or which ever is the 3 wire one) which is a push and twist with an offset (possibly) or even little nubs that make it hold in, then two contacts on the bottom for 2 filaments.
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these are tail lamps but does it somewhat look like the one on the left(the right one is the same generally speaking but the wires that went in was only 2 not 3)
or does it look different?
Every socket most likely used by GM exists in the dorman help section at the stores with large ones. Its not a 100% but its a pretty good liklihood. if your bulb needs a ground and its a twisty, you can cheat by exposing wire, and pinning it between the wall socket it goes in andrunning it out like that, because the part that the two nubs hold the bulb in is the ground for the bulb it just runs to a wire.