Six years ago I replaced the W5W incandescent front side marker bulbs in our 2015 Subaru Forester with amber LED bulbs:
The adhesive holding the LED PCB to the aluminum “heatsink” has fossilized and the strip on the right is peeling off (with the left one not far behind), which likely accounted for its loss of light output and flickering.
Tearing it apart reveals the LED layout and what looks like a bridge rectifier or a big resistor (to fool the CAN bus?) on a tiny PCB jammed inside the shell:
The other side of the PCB could be a buck converter:
In round numbers, we’ve driven 18000 miles at an average of maybe 40 mph over those years; call it 450 hours. However, the side marker lights aren’t on unless the headlights are on; we do very little night driving, which means those LED bulbs are the usual crap.
I replaced both front bulbs with a different design sporting two LED chips and we’ll see how long those last.
The Smell of Molten Projects in the Morning 
Comments
2 responses to “Auto Side Marker Bulb: FAIL”
I’m not impressed by those older LED bulbs, though the new ones look like they could be good quality. I’ve got over 40,000 miles on the 2016 Forester, and the majority of the headlight-on time is due to bad weather. So far this year, I’ve done night driving once. I’m still on OEM light bulbs, but will keep the LED ones in mind. Turn signal bulbs would be a likely target.
I think “mission critical” bulbs require DOT certification, versus general lighting bulbs, so I replaced the headlights & taillights with incandescent bulbs; turn signals probably fall into the same category.
I know for a fact that some of the headlights I see out there are not street legal …