I haven't been able to locate a OEM LED tail light for my 2004 LS430. It also seems strange for the LEDs themselves to burn out and they are nearly $300 online, so I figured I'd take the assembly apart and see if I could fix it. I removed the assembly and then I can see a circuit board full of resistors on the back that I believe to be tied to the LEDs (the turn signals are regular bulbs and accessible on the back). The board is labeled P3407M. I have not been able to locate any reference to it online and assume that this part cannot be purchased independently of the full taillight assembly. I tested each of the resistors for continuity with my meter, and three seem to be failing. I'm hoping to replace these and see if it resolves my situation. Resistors R1, R2, and R15 seem to be failing. The resistor markings are difficult to read and interpret on those resistors. I am wondering if anyone has the electrical diagrams for the taillight itself can look and see the details of these resistors for me.




Thanks,
Dustin

 

Nice for tackling this job message rkw he is the man to ask for diagrams

 

The service manual and electrical wiring diagram will not show these low-level circuit details, they only show high-level systems diagrams.

From what I see in your picture, those resistors are 2W and 0.62 ohms. Since you have tested those and they appear to be bad, you can replace them with equivalent-spec through-hole (not surface mount) resistors. You can buy such electronic components at DigiKey.

Your multimeter should be able to show resistance values and not just continuity - any resistors that show significantly different resistance values than the others would be candidates for replacement. You should also turn the board over and check the PCB traces, use your multimeter to verify the traces are good and not corroded or burned out.

A more interesting exercise would be to determine WHY the resistors failed or traces burned out. Speculating, it could be heat due to poor board placement resulting in poor air circulation, or excessive current due to poor circuit design/malfunctioning component. It is significantly less common for resistors to fail than for capacitors, but I suppose it's not unheard of.

 

Thanks for the response. The .62 ohm ones are the ones that aren't bad. I can read one is 82ohms and 2W. The others I guess I'll need to remove from the board to read as they are different and turned such that I can't read them. I will test the capacitors and circuit trace as well as i did find it strange that three resistors are failed. I mentioned continuity in my previous mail, though I did test for actual resistance and they had gone to infinity.

 

I would check the LEDs and trace down which LED went bad. If one of the resistors went bad it more than likely caused at least one LED to burn up. If you dont replace the bad LED(s) even if you replaced all the bad resistors on the board it still wont work.

 

I will do this if I need to, but I didn't immediately see how to easily take the lens apart to test that side. I would think if one of the resistors fails such that is no longer has continuity, then the LEDs would just stop as the circuit is no longer complete and I understand this to be a series circuit.

 

That would depend on how the resistor failed. If you are getting a OL on your DMM when you test the resistor there is a chance the LEDs are OK.

 

sorry to dig this up, but is this really the only way to fix these? one side went out when our LS was my wife's daily. and now that i have it, both lights on trunk lid are either half out or not working correctly. if i replace them, i'd be spending over $300 for the 2 trunk mounted lights. and then who knows how long they would last.

 

I hit the wiring harness on my right tail lights while swapping the turn signal out and noticed the LED tail lights flicker. I wiggled it some more and found that in one position they didn't light up and another they did -- so the connector pins or traces are likely very weak.

 

anyone have any leads on where i could purchase resistors like these? i found the 82 ohm resistors, but can't seem to find the .62 ohm resistors. i ended up ordering replacement trunk mounted lights. but i wouldn't mind trying to repair my old ones if this just seems to be a revolving door. this is my 2nd set of replacement inner tail lights. i don't want to have to buy a 3rd.

 

I would be surprised if DigiKey doesn't carry these resistors. They carry everything electronic-related: resistors, LEDs, mouse click switches, all kinds of everything - all the different packages, specifications, form factors, etc.

 

sweet. they definitely have the .62 ohm resistors @ the 2W rating. they have several different options. now i just have to figure out which ones will work for this application.

i have my 3rd set of inner tail lights in, but i don't want to install them until i get my soft close trunk feature fixed. in case the vibration of closing the trunk is really contributing to the early failure of these lights. Found someone that was kind of local that was selling the trunk latch/motor. going to get that saturday. fingers crossed this works.

thanks StanVanDam for the lead on that retailer.

 

Hey handy people, do you want my fritzing LED tail light? It sounds like some of you may know how to fix them. I just bought the new one for $200, but I am a big fan of recycling so if you would like mine to fix and use on your 04-06 LS, let me know.
No charge of course; I will ship it to you.
Right side (passenger) trunk mount, 81581-50050. Visually perfect condition, no fade and not a scratch.

 

I'll take them. Please pm me.

 

you got it, @science