Drivers side LED brake light dim

Yes, its true. The whole assembly will need to be replaced.

U can try eBay but be careful......it might have the same issue if its used.

 

It is true that if the LED light assembly has failed, then you would need to replace the entire taillight assembly.

However before you do that I suggest you check the wiring harness connections to make sure they are secure and that the ground connection to the body is tight. You'd probably be irritated if you replace the taillight assembly and find the same issue with the replacement unit. If you have a digital multimeter you may want to verify voltage to the brake light LEDs and compare to the other taillight, while you have a helper depress the brake pedal.

 

Patrick,

Where is the taillight assbly ground connection located?
Can it be tightened without disassembling too much?


Thanks,

 

I haven't needed to find this myself but believe that if you remove the plastic trim surrounding the hatch floor opening around where the lock is located, you will find some wires bolted to the body.

 

Yes, it's most likely the contacts in the connector. Sometimes just unplugging/plugging in the connector a few times may do it....
I twisted the contact pins slightly, with needle nose pliers, and also applied some contact cleaner (not sure if that's necessary)
It works again!

see this page
Dim Led Brake Lights On Prius - Hybrid / Toyota Prius - Toyota Owners Club - Toyota Forum