Bulbs are very hard to confirm visually - try a new one if you can't check continuity with a meter. PC boards that they plug into are a reliability problem as well. Harness sockets corrode and the pins in the circuit boards can get rusty. Aftermarket replacements available at the usual parts stores, it's not just a GM item.
Do either of you have a meter and know how to use them? I could post the pinout of the PC board if you want to check voltages.
Do either of you have a meter and know how to use them? I could post the pinout of the PC board if you want to check voltages.
