First post here: So I know that these bulbs go out quite a lot. My question has to do with the wiring of those lights. Separately I had the common issue with the halogen headlights burning out often but didn’t know enough to get the wiring harnesses replaced before the dealer paid option went away in 2019 (pathetic how that would have required both lights to be out in order for them to even mention it as a possible option). I’m wondering if this is a similar matter with the license plate lights wiring? Anyway I digress…. My current issue with the license plate bulbs is that I changed them to LEDs that are great but for some reason only one side will illuminate. I have a whole bag full of these little buggers to replace the other incandescent/halogen side markers etc once they fail but I can’t seem to figure out why only one of the sockets is working with the new LEDs. I no longer have the incandescent bulbs to see if one of those would work. Does anyone know if the license plate lights are tied to a single harness or two separate ones? We live in Southern California so I don’t think water or elements got underneath the lens causing any contamination on the contact but I guess I can try cleaning it. I would have imagined I’d get some amount of power coming through it to the point that the new LED would at least flicker on/off but that’s not the case. One side works perfectly and I even tried placing that LED into the other side to see if I simply had a batch of bad LEDs except for that one.
If you look at the LED bulb there should be a red dot next to one of the terminals try flipping the red dot over and see if it works on the side that's not working pull the lamp out the bulb look for the dot see if you can see where it was put it back in now pull it out and flip the dot over to the other side and stick the ball back in the license plate light Is it on now? You can take a DVOM and check from body ground to that individual socket that you are unplugging to put the bulb in and see if it has 12 volts on it when you have the switch and the first position I'm thinking so because the one side is working but with LEDs different than incandescents which is what you took out one side will go in one way and the other side if you plug it the same way many times won't come on you flip the bulb over
Hi Tom, Thanks for your reply and the suggestions. Not exactly sure what a DVOM is but I don't think I have one of those. I'll look at one of the LEDs in the bag to see if there's a red dot marking anywhere near the contact point. Regardless of whether a red dot is evident on the LED I will also try turning it 180 degrees and reinstalling it to see if that works. Seems odd if that may actually make a difference as the incandescents didn't require a certain orientation but this is why I try automotive web forums. I never know what I may learn! So not sure why an LED would need to be turned 180 but its worth a shot. Will circle back to report my results. I do have a touchless volt meter for testing if a home electrical outlet or wires have power or not, but I'm not sure if that will detect whatever level of voltage it is that runs through the Prius wiring for the license plate lights that I'm sure is far less than a home. Probably worth a look if the LED 180-degree turn approach doesn't resolve things. I think I have another wired one in my toolbox that may detect lower voltage levels so I'll see if that can provide any info on the power status of that socket as well. But lets hope the 180 turn does the trick!
Update: SUCCESS!! So you were absolutely correct about how things were connected. I didn't see any obvious markings on the LED but I rotated it 180 degrees. I noticed that the plastic connector appears to have two ways that it can be clicked in to the bulb carrier (also at 180 difference in the orientation) and I suspect that it was either the orientation of the LED or how I had that connector clicked together to the bulb carrier. Not sure if I had the connector clicked in any differently than it was when I worked with it today, but I know the LED was rotated for certain. The takeaway here is rotation of the LED is one thing to check and failing that, the connector also should be rotated and reconnected to the bulb carrier as another check. So glad to get it working again when I thought it would be a much bigger problem. Thank you Tombuckt2 and this forum! Cheers!
I hope so with LED lamps like for turn signals and marker lights and all that usually one side you plug in and it works and the other side you plug in and it doesn't you flip it over plug it in and it lights right up It's just weird like that usually there's a little red dot so you know which way you're or I'll say OSRAM Sylvania is very good about that.
Well, LED stands for Light Emitting Diode. The light-emitting part is self-explanatory. A diode is a thing that conducts electricity in one direction only. An LED is one of those, that emits light. Some LED retrofit bulbs are more than a simple LED, and also have a bridge circuit to make them work either way you plug them in. But many don't have that, and you just have to plug them in the right way.
