Good morning everyone. I've got a 2005 Prius with 130k miles. I've only had it about 8 months. Well about 2 months ago, I was hit with the dim taillight issue so I bought an OEM used unit off eBay and replaced it easily. Now, 2 months later, this same taillight is sporadically dim too. I suppose since the replacement light was used, its possible that one could be going bad too. But it seems odd that it would fail within 2 months and be the passenger taillight both times. I drove a 1995 Mazda to 300k miles and never had to touch so much as an interior bulb. Now I'm potentially having to replace the same taillight twice within 2 months on a car that isn't really that old. Any ideas?
It sounds like corrosion in the cabling or unit, or a connection problem. If the other light is good, it's almost certainly connected to it - check the connection between it and the good lamp, and all the earth connections.
Do you mean the brake / signal lights or the nighttime lights? I believe the brake lights are LED by the other ones are bulbs.
Thinking back to my younger days, lighting faults were frequently career by a bad earth connection at the lamp. Corrosion in my old cars was usually the cause.
I have seen individual LEDs get "leaky" and fail. Many times the LEDs are connected in series so one bad one could affect several. I wonder how much a new panel is?
Yeah but to my point in the original post, I either have terrible luck for the replacement to go out on the same side, or something is up with the connection.
This isn't a Gen 4 - but a 2006, (I reported the post suggesting it move to the right forum) which I don't think had LEDs - though I could be wrong. LEDs don't go dull - they just stop. There's always one cable to the back of the car, part of a wiring loom generally. It will often go to one side, then daisy chain to the other side. If one is working, follow the cabling, earth connections, bulb housing etc to work out where power isn't getting to the other side. I'd be checking or getting your wiring checked rather than replace the lamp.
Yes, the Gen II brake lights are LED, all others incandescents. The LEDs are not user serviceable, so if they fail, the remedy is replacing the whole light unit. I did read of one post where a guy with electronics knowledge managed to open the light unit up and effected a repair by unsoldering the LEDs and replacing with new LEDs he sourced. It wasn't technically hard to do (if you know what you're doing), but isn't easy as the unit is not designed to be serviceable. Although he had the satisfaction of fixing it, he said he wouldn't do it again, just because it was so fiddly.
He's also talking about a "taillight", not brake light ["this same taillight is sporadically dim too"]. My experience with LEDs, if it was an LED, is that they either work, or don't work, they don't go dim.
I have replaced dim LEDs although that was a number of years ago. Materials and manufacturing may have changed the likelihood since them. Otherwise look for bad grounding of the light having issues.
