Yesterday it came up that my left brake light wasn't working. . I changed the bulb and it was fine and then told me my right rear turn signal was now not working. I have been driving my new to me, 2000, 3.0 for 6 months or so. . My friend who owns a shop figured it out Someone had replaced the tail light bulbs with LED bulbs. Switched them out for regular bulbs and all is good again. I still can't figure why all was well and then/ the LED's caused a problem

 

I take it that in the 6 month before the LED bulbs worked OK? If so, I do see no reason as to why the LEDs (as in "the technology LED") should be responsible for that problem. Of course, LEDs can fail, just like filament bulbs. Other than that I think it is tricky to find the right LED bulbs for Jags to start with (in the rear lights), as Jaguar frequently "presents" plus in the socket where minus should be, and visa versa, which does not matter for filament bulbs, but it is a problem for LED bulbs - but if that is the issue, it means that the rear LED bulbs should not have worked in the first place.

 

Why did the LEDs last six months? Probably cuz he got lucky! Seems most fail long before that. In my over-inflated opinion, the QC and reliability of Chinese LEDs is pretty dismal.

Many newer vehicles have circuitry to monitor for incandescent bulb failure. Not sure of the exact details, but the controller probably monitors resistance at rest or amp draw in use. Most automotive LED bulbs, laughably advertised as drawing less power, have integral resistors to mimic the characteristics of incandescent bulbs. The LED itself could fail but if the resistor is still intact, the warning is defeated.

So where is this heartwarming tale leading? My limited experience with LED bulbs is from installing some inside my camper. These were for general illumination so did not have the spoof resistors typically found in exterior lamps. But of the six pack I purchased (Fling Dung brand), two failed almost immediately. Two more failed within months. The last two are still going strong after several years. Extrapolating my results here and with Chinese goods in general, QC is not a highly esteemed career field over there.

FWIW, we see similar issues in aviation. LED bulbs have been retrofitted in many applications for their supposed reliability. New planes are delivered with them. Boeing even proudly stated certain multi-segment arrays would last the life of the plane. We lowly mechanics have learned otherwise.

 

> In my over-inflated opinion, the QC and reliability of Chinese LEDs is pretty dismal.

Yes, Karl, I wanted to write something along those lines as well, but I did not want to make it too complicated. That may also be the case - as I indicated myself with "Of course, LEDs can fail, just like filament bulbs."

One other idea I had: I wanted to suggest that Wild Cat connects the supposed to be damaged LED bulbs directly to a battery (better both ways (reg. plus and minus) just to be sure), to confirm that the bulbs are damaged, and that we do not have another case of contact-corrosion in the sockets.

> Extrapolating my results here and with Chinese goods in general, QC is not a highly esteemed career field over there.

I am aware of that. Chinese companies "outsourced" their QC-department a long time ago to the consumer, i.e. the consumer is the one, who will know about faults in their products - China and Chinese companies do not care. However, especially in regards of those interiour dome lamp-bulbs: That is how things work these days: You buy 10 from China, if you need 2 and then you just scrap the damaged ones - that is still the cheapest solution...

> New planes are delivered with them [LEDs]. Boeing even proudly stated certain multi-segment arrays would last the life of the plane. We lowly mechanics have learned otherwise.

Here is an idea for the those rocket scientists designing planes - a logical one, as Spock would say:

As everything in aircrafts is supposed to be designed with redundancy [apart from - strangely - the acme-nut, which when "strips" by the jackscrew of the horizontal stabilizer trim (in case of poor maintenance and unchecked wear) of a McDonnell Douglas MD-83, to the effect that the plane then just falls out of the sky], why not design all warning lights in aircrafts with redundancy (filament and LED in parallel)?

 

Not quite exactly what you proposed, but Boeing did (was forced to do?) something similar, as we drift further off topic.

The 757/67 series was designed in the late 1970s. Multiple instruments and warning indicators were consolidated into CRT screens. At the time, such new-fangled technology was considered unproven. The “fix” was to also add individual warning lights, in addition to the on-screen displays.

Turns out the display screens were highly reliable. In the rare case of a screen failure, the remaining screens could be quickly reconfigured to show the same data.

Meanwhile, guess what has become horribly unreliable? The individual warning lights. They give us nonstop grief, and were considered the reliable technology back in the day.