2002 ASTRO Van Tail light Mystery bulb

washburner

My 2002 ASTRO tailight has two ordinary bulbs for the lights, turn and backup.
In the middle of the housing is a small silver bulb about the size of a pea. I broke it trying to remove it. I CANNOT see what it does - Everything works after I replaced the regular turn signal bulb. I searched and the socket looks like a "SIDE MARKER" socket - but there is no side marker in the rear. And I cannot find a replacement bulb spec. What the heck is that small bulb in the middle for??

washburner

Here's a snapshot of the opened tail light assembly. The socket in the middle is the mystery -- It is neither the brake, backup, turn or running light. It was a small silver bulb that broke.

takumi_

Not 100% sure but It could be a 194 peanut marker bulb, it's silver / dark silver cause it was burnt inside the bulb

washburner

Thanks - It is a peanut size so I will check that out. Still, cant see what it does. I broke the right side peanut bulb - but it still looks the same as the unbroken left side.