There are multiple kinds of LED replacement out there for different use but if you just want to replace the existing 194LL with a whiter light and not necessarily a lot brighter I have found as close to a perfect replacement as I think possible.
These are almost the exact same size as the bulb but are still polarity dependant. Probably not enough room for a bridge rectifier on the circuit board. They are flanked with LEDs on both sides. They are also very cheap to buy. They work well when size and length matters.
I got these on
I will show pictures of each one 2 inches from the LUX meter at X10 scale, these should all read between 1000 and 4000 lux even if they advertise more.
A 194LL gives out the lowest intensity at 1000 Lux/2"
Almost double @ 1860 Lux/2"
This one is over 4 times
This one was the brightest but is a dual flank and sends barely any light from the end.
This one although only 3 times as bright has 2 LED on the end and produces light all the way around, but I found these not very reliable or durable.
This is also a very good replacement but more money...