Incandescent bulbs work, LED do NOT work

Same here... Put in a couple of LED marker lights they are polarity sensitive.. one other issue too. about 5 fuses later I figured out the other issue. work great now.

As I and others said. Some add a diode bridge so the polarity is not an issue
Some do not.
There are a couple base designs
The "Bayonet" base (1136/1141 are two examples) you can not "Turn it over" unless you make a 2 part bulb Some companies do that some use bridges and some you have to rewire.

The Wedge base.. Well if they don't work try turning 'em around (My Marker light was like that).

wa8yxm wrote:

pnichols wrote:

However ... quality LED bulbs do have circuitry driving them that doesn't care about the incomng 12 volt polarity.

Well yes. but LED's come in baically 3 (time many) Types only 3 affect this thread however

Some: as you point out, use a bridge so they work no matter which lead is positive

Some you can turn the lamp over or you plug it into the adapter the other way

Some you have to re-wire the socket.

I have all 3 kinds in this RV.

The "many" refers to Lumens and color temp and design of lamp and so many things that have nothign to do with this thread for me to list.

But as I said the led is like a check valve in a water line. Water only flows if the INLET is "positive" (has pressure) (Yes this too is not correct for electricity but I'm trying to KISS the issue)

If you install a check valve backwards nothing flows
Same for the LED.

I will also add, requiring the correct polarity on a LED bulb does not equal cheap. I have encountered can-bus compatible bulbs that do require to be inserted the correct way. They were not cheap quality.

However ... quality LED bulbs do have circuitry driving them that doesn't care about the incomng 12 volt polarity.

Read the answer to the 2nd FAQ question down from the top at the rvledlites.com website. RV Led Lites sells only high quality LED lites - many of which don't have many of the problems you get with cheap(er) LED lites:
https://rvledlites.com/greggwilsondesigns/full-width/

I have been burned by cheap ebay RV LED lights - they flicker when the water pump comes on, they smell of ozone, and they dim if left on for a long time.

But **** if I'm spending $16 per bulb for lightbulbs.

pnichols wrote:

However ... quality LED bulbs do have circuitry driving them that doesn't care about the incomng 12 volt polarity.

Well yes. but LED's come in baically 3 (time many) Types only 3 affect this thread however

Some: as you point out, use a bridge so they work no matter which lead is positive

Some you can turn the lamp over or you plug it into the adapter the other way

Some you have to re-wire the socket.

I have all 3 kinds in this RV.

The "many" refers to Lumens and color temp and design of lamp and so many things that have nothign to do with this thread for me to list.

But as I said the led is like a check valve in a water line. Water only flows if the INLET is "positive" (has pressure) (Yes this too is not correct for electricity but I'm trying to KISS the issue)

If you install a check valve backwards nothing flows
Same for the LED.

Sooo, thanks again all! I opened up another fixture and noticed a white plastic wire plug that has the black and white wires in respective orientation. Pull the problematic fixture out and guess what? No factory looking white Gizmo! But in it's stead, a wire nut! The issue isn't with that soldered ma do dad, but with the actual wires coming INTO the fixture! Clipped, flipped, tested, and Bam! LED work! Now to tidy it all up. I heart you all!

Munk888 wrote:
They look the same! Cept one works with LED, and the other don't...

That doesn’t mean they are the same on the fuse block or power source. Did you check the polarity of both fixtures with a meter?

So, finally getting around to working on this, and the wire setups are identical! Let me try to get non-gigantic pics.

pnichols wrote:

However ... quality LED bulbs do have circuitry driving them that doesn't care about the incomng 12 volt polarity.

All of mine have this, so I incorrectly assumed it was a standard feature on all of them these days.

pnichols wrote:
However ... quality LED bulbs do have circuitry driving them that doesn't care about the incomng 12 volt polarity.

Yep. It's called a diode bridge and is the same device that is used to convert AC to DC. In an AC application, the diode bridge takes the alternating forward and reverse polarity and "converts" it to a single polarity. In the LEDs you refer to, it takes either forward or reversed polarity DC and converts it to forward.

https://en.wikipedia.org/wiki/Diode_bridge