Just picked up the clear side marker and turn signal lenses from 914Rubber. Looks stealth on an ivory car.

Also picked up the LED side marker lights at the same time. Curious to know why the passenger side won’t light with the LED, but will with the standard bulb? Drivers side works. Switching the bulb doesn’t solve it.

Too little resistance for that ‘circuit?’

If the incandescent works in the same outlet but the led doesn’t then it’s either the led specifically or the resistance… that’s my bet anyway.
Did you try the working led from the drivers side? Not sure what you meant by “switching bulbs”

I had the same problem with mine. Wiring for the LED is specific. The regular bulb will work with the wires connected to either terminal.
If it's not working, you'll have to switch the wires on the back of the light socket.
It should work then.

I tried each LED on driver and passenger sides. Both worked, but only on the driver side.

I might be missing something, but both LED bulbs work, but only on the drivers side. A regular bulb works on both sides.

Do you mean that I might need to rewire one side, but not the other?

If you can look at the wiring of the socket on both sides, you can confirm that polarity is not reversed on one side. I’ve heard urban legends that classic Porsche light wiring isn’t always negative ground, but I haven’t run across that in my own experience.

Yes, that's what I mean. You'll have to switch the wires on the back of the light housing that is not working. I bought a set of side marker lights from Spoke and had the same problem. He told me to flip those two wires and it would work.
And it did.

That’s an easy fix. Thank you.

It is somewhat common for these older vehicles that the wires were disconnected and reconnected at some time during repairs or body work. The socket has 2 spades and 2 wires connect to them and sometimes the wires are reversed.

If reversed, the voltage on the bulb is reversed and the button of the bulb base is ground and the case is 12V. An incandescent bulb is not polarity sensitive and works regardless of the wiring. The LEDs are diodes and current only flows in one direction.

I've worked with a couple of folks with 911 front sidemarkers with the same issue. Also on the 911 the 3rd brake light can be wired in reverse. One guy was so adamant that I wired the LED 3rd brake light backwards that he cut the wires on the LED board and reversed them.