Full disclosure: this isn't for a 3rd gen. But it's a GM vehicle from the same era, so it very well could use the same bulbs as a 3rd gen. My dad is a restoring an '89 Chevy Celebrity (don't ask me why!) and the SES light on the dash does not illuminate. We pulled out the instrument cluster from the donor car's dash (I think... I can't recall if the cluster is from the '89 or the '87 donor car) and removed the SES bulb. It's very small and is permanently mounted to a plastic clip that twists into the cluster assembly.

I tested the potential replacement bulb w/ a multimeter and found infinite resistance, even though the filament appears to be intact. I then connected it to 12V from a battery and it failed to light up. There were 3 more bulbs of the same type in the cluster, and they all tested the same way.

I tried searching online, but I can't find this specific type of bulb. Most search results come up with 194 bulbs, which are also used in the cluster. But this particular bulb is definitely not that. The pix show the bulb in question (w/ the green plastic base) and a 194 bulb in a plastic clip for comparison. Any idea what bulb this is and where I can find a replacement? And what is the blue thing inside the glass -- maybe a resistor or capacitor?

 

Should be a #74 bulb

https://www.bulbtown.com/74_Miniatur...Rated%20Hours.

 

Not POSITIVE: but pretty sure that bulb was also used in the 95-2002 ( or so ) style S10, S15, Blazer/Jimmy. Next time your at the junkyard pull the sun-visor down, rip off the plastic vanity mirror bezel and you'll expose the 2 bulbs.