Side marker/corner lights

Greetings.....

My '94 Caprice does have cornering lights, but I can't for the life of me get confirmation of the LED part number I should be looking for to replace them, because one is already out and the turn signal to that side doesn't work.

To be clear, these can't be 194s; those seem to match up with the smallest bulb in the taillights, but that won't fit in the corners up front.  The ones I'm looking for are very small and thin, about half the width of a 194 from the back end by comparison.

They might be 74s, but I hesitate to prejudice any responses here.

Anyone know what I'm talking about here??

Are you looking to replace the side marker lamp or the cornering lamp?

I'm trying to replace what I think is labeled "front side marker lamp (Chevy)" in this diagram.  To wit, those tiny bulbs inside these bezels:

https://rb.gy/sfwgah

into harnesses sort of like these:

https://rb.gy/37o0w1

Ok - so the "Front Side Marker Lamp" and the "Cornering Lamp" are in the same housing, but different circuits.

The front side marker lamp is "high resistance" = small bulb (24), low current
The front turn lamp (A) is "low resistance" = big bulb (2057A), high current
The front park lamp (B) is "high resistance" = small bulb (2057A), low current

When the headlights are off and a turn signal is on, power comes down the blue wire (light blue for Left, dark blue for Right) and powers both the Front Side Marker Lamp and the Front Turn Lamp.

The Front Turn Lamp has a direct path to ground so it lights up when powered by the flasher.
The Front Side Marker Lamp grounds through the other two front park lamps filaments so it lights up at the same time as the front turn lamp.  Current flows from B to A on the front side marker lamp when it's lit.

When the headlights are on, all the parking and marker lamps are lit by the grey/black wire from the headlight switch.  Current flows from A to B on the front side marker lamp and is grounded through the Front Turn Lamp bulb filament.  When a turn signal is turned on, there is now power on both sides of the Front Turn Lamp which shuts it off when the front turn lamp is lit so the two lights alternate, when one is on, the other is off.

So, current flows both from A to B and from B to A in the Front Side Marker Lamp depending on if the headlights are on or off.  For this reason, most LED's won't work since LED's are designed to be polarity sensitive - it'll work one way, but not the other.

Rumor has it that there are LED's on the market that are bi-polar and would work in this application, however you also have to consider the front park lamps are providing ground so if those are swapped with LED's, they might light when you don't want them to or not at all.

Hope this helps explain how this circuit works and why.

Personally, I'd put in some long life 24's

Bulb List

https://www.impalassforum.com/threads/all-bulb-numbers-list-anyone-got-one.231083/#post-2163304

Well first, Fix Until Broke, many thanks for that exhaustive explanation.  I'm hard-copying this.  That said, it looks as though the bezel I have has only one socket, not two -- it has the tiny little one, not the larger one.  That's what I get for doing this in a hurry, and what probably explains why I can't find agreement on the bulb size I need.

On a side note, I've upgraded the headlights and inboard turn signals (adjacent to the grille), and I've found that turning on the headlights shuts off the turn signals and four-ways.  Replacing the turn signals restores them.  I'm going to have to go over all of this much more carefully.  Thank you again!

Caprice WAGONS do not have cornering lights. Just signal lights. You can add them, though. Just need the harness from a sedan or Roadmaster wagon.

A 1057 replacement bulb will work. I have them on my OCC.